Genuine countertake: neither
Professor Umbridge is a sane and moral actor, who seems evil when viewed through the eyes of a particular teenager. Take a look at her major decisions in pseudo-chronological order*:
"'I'll tell you what it means,' said Hermione through gritted teeth.
'It means the Ministry's interfering at Hogwarts.'"
Terrific, oversight seems very reasonable. The ministry is only there because last year the headmaster decided to bring back a sporting event that was cancelled because of too many deaths, and a student immediately died again. The surrounding events are confusing, (even SE has some questions), but it's rooted in the fact that the headmaster hired a close friend despite everyone saying he's unhinged and the friend wound up being a serial-killer. The headmaster didn't notice his old friend was actually someone completely different. This is different than the close friend Dumbeldore hired two years ago who attacked students as a werewolf... or the hire four years ago who attacked students in the murder-dungeon (why is that in a school, again?)... or the hire three years ago who attacked students and tried to wipe their memory (same year the board of trustees voted to have Dumbledore removed for incompetency)... In fact, the ministry wouldn't be here at all, even given all this, if the headmaster had been able to hire a new DADA teacher.
- She doesn't want to teach applied DADA. Makes sense to me, (others at SE are confused about the curriculum too); the kids aren't learning math, should murder class really be anything more than academic? Yes, the last teacher had them practice torture spells, but I agree with Umbridge tbh, probably not a terrific idea. You can disagree with her pedagogy here, but it's certainly not evil. Muggle parents get upset over books with swears in them, I can't imagine what they'd say if we were practicing torture methods in gym class.
- Umbridge doesn't believe Cedric was murdered or Voldemort is back. Um... should she? The facts:
- People died... at a death game. Dumbledore brought back a game cancelled because of all the deaths - Dragon-Provoking was round two - and someone died. That isn't.... super duper unexpected.
- Harry is traumatized and not making much sense After returning Harry is immediately assaulted by a teacher. He starts babbling things like 'the person I fear most came back from the dead and all these important people in my life were Death Eaters. Oh no not the two death eaters sitting with you at the time, those were the ONLY two that didn't show. And my dead parents were there too! Then the portkey brought me back to here for some reason'. Okay... Keep in mind other students had been confudus'd or imperious'd already during the event.
- The story is full of holes, with an obvious alternate explanation. The portkey thing is the smallest part that doesn't make sense. And you defeated Voldemort AGAIN to escape?! The serial killer in the room has claimed responsibility for the death of the student, which kind of fits.
- Dumbledore makes a terrible case. He doesn't say: 'this is kind of my fault,' or 'let's talk about this away from the traumatized children'. He says: 'you have to get rid of ALL your prison guards RIGHT NOW.' Hold up Dumbledore, for a smart guy that wasn't a brilliant thing to say.
- Nobody else believes Harry Maybe that's why not just the minister of magic and the major newspaper, but the International Wizemgemot too think he's crazy. Of course, Harry claims all those people are bought-and-paid-for... but do have any independent reason to believe that about the international community? It's not unheard of for famous people to become ranting conspiracy theorists in their old age, and Occam's razor agrees with Dolores and almost everyone else in the wizarding world on this one. If this makes Dolores evil, is like, the whole wizarding world evil too?
She has Harry write lines for detention, in his own blood, leading to permanent scars. This is definitely icky, but lets look at it in context.
- This is a milder wizard detention than others we've seen The morally unimpeachable McGonagall's detention pick for first year students out past curfew was going into the forbidden forest, unaccompanied except by a fearful dog, to hunt down a thing that was killing unicorns. Wait, what? Everyone almost died to a monster, unsurprisingly, until a centaur saved them against its nature. Especially in comparison to what Filch admits happened in living memory, writing lines doesn't seem so bad:
"It's just a pity they let the old punishments die out... hang you by
your wrists from the ceiling for a few days, I've got the chains still
in my office, keep 'em well oiled in case they're ever needed" - Filch
- Harry can't stay out of detention It's extra gross because of the blood component, but that's mostly for ick factor - the scars clearly aren't meant to be permanent (other students have them wear right off) - but Harry keeps getting detention. Unjustly? He stands up the very first day of class and shouts at the teacher that she's a liar. He disrupts constantly. He gets into fist fights, and tries to start an army at school. From Umbridge's perspective, she has a very distributed young student, and giving him detention far lighter than McGonagall assigned to mischievous freshman is about in-line with what we've seen in-universe.
- She tries to stop Dumbledore's Army. Umbridge gets a credible tip that a troublesome student is trying to - checks notes - start an army to overthrow her and the government. What does she do? Requests that official school clubs register with the school, something that almost every school in the world already does. (It's also a good way to allocate funding - two birds one stone!) She doesn't go on the war path or interrogate anyone out the gate. It's only when the students go ahead and secretly start revolution club anyways that she starts a low-key investigation, with the support of many of the existing students at the school. You know, the ones who want to learn from the book, and not foster guerilla armies.
- She suspends the Griffindore Quidditch team.
- Nothing she has done has gotten through to Harry - he's still on a downward spiral that (SPOILER) leads to him getting his godfather killed and wrecking Dumbeldore's office. Literally no adult is supporting this kid emotionally. Other members of the Quidditch team - the Weasley twins - are so well known for their misbehavior that it's a meme; they wind up dropping out and ruining exams. Maybe this is what will get through to them that they need to behave - can you imagine if half of the soccer team at your highschool was constantly in detention and violent? Telling the team they need to behave academically to maintain their sport sounds pretty reasonable to me.
- What happens when Dolores gets overruled? The very first game the players get into fist fights. Yikes, guess she was right. Btw, what's McGonagall's game here in going over Umbridge's head - McGonagall believes there's a serial killer mounting an attack and this is the hill she dies on?
- She files for more power. What other options did she have? She was a government auditor brought in because students were routinely dying or getting maimed, and she literally can't discipline students by - checks notes - kicking them off a sports team? She's being blocked at the most basic levels of discipline.
- She audits the teachers, firing good ol' Hagrid and Trelawney.
"'I just think she's an absolutely appalling teacher and a real old
fraud." - Hermione.
"The fact that Hagrid was now on probation became common knowledge
within the school over the next few days, but to Harry's indignation,
hardly anybody appeared to be upset about it".
This is strong evidence in her favor. If she was really just trying to set up Harry and Dumbledore, she would have immediately gone to fire McGonagall and Snape, his two closest allies. After all, she had wide latitude in interpreting the audit results. But she doesn't, she passes McGonagall with flying colors and she questions Sanpe on his former ties to terrorism and evident lack of full trust from the headmaster - both fair questions. Trelawney isn't even a real teacher, she's just a pawn in some long term chess game that Dumbledore is playing (he laughs that he'd give her a raise after her third actual prediction). The trio feels bad for Hagrid, but Hermione had long said he was a terrible (sometimes dangerous) teacher with no qualifications who was hired because... why again? The trio didn't even want to take his class, even as his close personal friend. The school has had a lot of hiring problems recently, most famously the serial killer masquerading as Dumbledore's best friend: these are the exact type of things a responsible auditor would scrutinize.
- She threatens Harry with an unforgivable curse and Azkaban. Let's look at the scene: a lot of waving her wand and dramatically flipping over Fudge's picture. Not a lot of actual spellcasting. If you think Umbridge is evil, then the will to do this fits with her style, but even so, it should seem extremely out-of-character. She follows the book to-the-t. She doesn't fire McGonagall or Snape, even when legalistically she could, because she honors the intent of the law religiously. She concedes immediately when Dumbledore hires a new Divinitation professor and insists Trelawny stays on campus even though it's all highly irregular. She always diligently files for more power, she doesn't stretch the power she already has - bureaucracy is her favorite thing in the world. Can you really imagine her casting unforgivable curses not just in front of a ton of witnesses, but the children of important and powerful Ministry Officials, like Malfoy? Sure, they like her, but that sounds like a rumor that'll spread. And for what gain? To save some time that doesn't need to be saved. This seems like textbook every teacher or procedural-cop-show ever: "oh if you don't confess right this second we'll expel you/throw you in prison/tell your parents/whatever." Threatening emptily is very in-character - and it worked (sort of). Actually doing it would be wildly un-Umbridgey and downright stupid.
- She insults the centaurs. Out of universe, centaurs may be stand-ins for any number of marginalized groups. But in universe... they... don't really make great metaphors. They brutally attack each other and school characters repeatedly. She seems afraid of them immediately and they... violently assault her leaving her catatonic in the hospital. They were provoked, surely, but saying they were justified is a lot of latitude. We see this with Werewolves too - out of universe, we think of them as symbols of discrimination, but in-universe, the only two Werewolves we see are Lupin and Greyback. The former - a certified "good guy" - attacks and almost kills his best friend and students because he loses control in his first book, and the latter gleefully attacks and murders people constantly. Without projecting our out-of-universe biases, I'm not sure we have enough information to say whether the metaphor really holds up.
- She sends the dementors after Harry. But does she?
"'It means that I think they were ordered there,' said Dumbledore.
'I think we might have a record of it if someone had ordered a pair of
Dementors to go strolling through Little Whinging!' barked Fudge.
'Not if the Dementors are taking orders from someone other than the
Ministry of Magic these days.'"
Right, Dumbledore thinks Voldemort did it. In fact, this is the exact thing Dumbledore warned Fudge about at the end of the last book. In the next book it's confirmed Voldemort is controlling the dementors, and in this book there's a prison break that highly suggests it. How would Umbridge have done this without a paper trail? Waltz up to the most guarded prison on Earth and politely ask the guards? More to the point, why would she? Did she genuinely hate this kid she'd never met so much to take such a huge personal risk? Again, it's wildly out of character - everything we directly see her do is to-the-letter legal. She loves laws. So why'd she say she did it? Well, it's in the same monologue as (8) - Harry challenges whether her threat is serious and she goes 'oh I'm super duper serious, I even sent those dementors just like you thought I did!!'. Right, sure. This seems like more evidence that 8 was empty threats. Even when Umbridge is headmaster, she doesn't expel Harry without cause even though she could, but she risks it all to kill him out the gate? Hmm.
- She participates in a court against non pure-bloods. Not a great look. But keep in mind she'd had a Horcrux on for months at this point. When Ron had to carry the same Horcrux, on and off, for a little while, he straight up abandons his friends and the fate of the world and goes home to his brother. Ginny hung out with a diary Horcrux and tried to murder half the school and a few chickens and a cat. We don't damn those characters, so let's give Umbridge the same benefit.
- Other answers make a few claims I disagree with.
- "Umbridge relishes her power and abuses it openly and cruelly" and "Umbridge derives pleasure from emotionally hurting Professor Trelawney" - seems to be a little editorializing here. We don't know what she relishes and I disagree that there's evidence she abuses her power, ever. Every time she smiles Harry calls it an evil or conniving smile, but if it was an awkward smile or a polite smile he'd probably see it the same way, because he hates her. T
- "it is forbidden to give students Veritaserum": I don't know where that claim comes from: all we hear is
"Now, the use of this potion is controlled by very strict Ministry
from Snape, and Umbridge would be the perfect person to apply for permission to the ministry.
- "Umbridge was prepared to send Harry to prison without a trial"; only relevant reference to Azkaban I see is
"you will be formally charged, then sent to Azkaban to await trial"
... which is by Fudge to Dumbledore, and explicitly mentions a trial.
- "really hates children". Yes, she says this when the children trap her between a giant and centaurs about to attack her. It seems tongue-in-cheek to me. Moreover, she's a high-ranking government official who was willing to teach, not a teacher by nature. Not liking children but teaching for the good of the school out of the kindness of her heart seems like bonus points to me.
What do characters outside the trio think?
Percy praises her. Fudge has promoted her to undersecretary. And importantly, Scrimgeour keeps her onboard too. We can nitpick the first two, but Scrimgeour is a pretty ethical dude - he dies under torture to keep Harry safe. Madam Bones seems to work closely with her and everyone loves Bones. The people who have worked with her all give her the marks of a practical and diligent public servant.
Through the eyes of a teenager, Umbridge is the ultimate evil - just like we all thought our least-favorite teacher was in high school, but with higher stakes. I think this is a good thing - Umbridge is written well as a character with enough internal justification for her actions that perspective matters, and that's rare in a children's story chalk full of serial killers. Taken together, a little supervision in a school where children are constantly dying or being put in near-death scenarios sounds not just great, but the minimum responsibility of the government. Dumbledore may be a great resistance warrior, but he's a questionable educator. Harry might be a decent chosen-one, but he's not a model student. Umbridge may not be a good enabler-of-prophecy, but do we need to keep ragging on the one teacher who actually wants to school to be a place of... learning (no offense to Mr. Binns)?
(*) I've pulled in info from the books too, which I hope is okay here. I think it's important to understanding the character in the movie