While several aspects of Birdman (2014) have been discussed and debated, with some people agreeing and others disagreeing with the merits of the continuous structure of the film, the (lack of) importance of the romance angle, and whether the film is ultimately simply a narcissistic exercise, there has been virtually no debate and visible disagreement on the fact that the ending is a "happy" one.
This seems odd to me, since the progression of events seemed to indicate a distinctly unhappy ending and a resulting broader (and unhappy) implication for the character, not a redemptive one.
To understand my incredulity, consider the basic kernel of the story transposed to real life, and see if the progression of events could be termed "happy":
"Dunce" kid wants to score big in literature. He is good at sports and is "popular", but for whatever reason, literature does not penetrate his skull. But he makes up his mind that he wants to achieve that, and assembles the right collection of books to make a genuine stab.
He is continually called a dunce, bullied by the teachers and told that "he will never succeed".
For a brief moment, he strikes back at the said bully-teacher, giving you - the viewer - some mild hope that there is a message of equality and redemption hidden in the movie after all.
Soon after, dunce kid loses it, gets up the next morning, realizes he will never be anything more than a jock, writes a long suicide note addressed to the teacher describing how shitty he is and how there is no hope for him, and then offs himself.
Teacher receives the blood-spattered letter, and instead of being horrified by what happened to the boy, or the least bit compassionate, is impressed that the suicide note is "completely honest", has some "much needed blood" and is in impressive handwriting.
She then writes him a note back, "You are ignorant, and you will always be, but the honesty of your depression is awesome!!", and enrolls him in 10 literary competitions.
Meanwhile, the boy has failed to even kill himself, and now faces the prospect of 10 literary competitions, where - according to the evidence presented so far - he can only impress or even compete, if he is depressed all over again, permanently accepting that he is shit and not allowed to have a single smidgen of confidence or self respect.
Because if he is not depressed, he can't emote! ..As per the movie.
This doesn't seem in any way like a happy ending.
I know the example is forced and exaggerated, but my point is to highlight the extremity and ridiculousness of emotions Riggan must have been going through, and the ridiculous situation he appears to end up in.
It is possible that this interpretation of the series of events is not correct (in terms of the emotional keystones it hits), but if it is, I completely fail to understand how this is being interpreted as "happy" for Riggan, rather than depressing and intensely horrifying!
Now there are alternative explanations for the ending. One from yurnero's answer being:
Finally, some people interpret the post-suicide act as Riggan's pre-death imagination so the bullet 5 in your post doesn't have to correspond to a real event in the movie
This would in fact make sense, and would count as an indirect "victory" even within the context of a tragedy. Because while Riggan could not earn legitimacy during his life, he put the only thing he had - his real life depression and lack of sense of worth - into one last performance, and signed off on a high, finally in control of his legacy the only way he could.
This is the only interpretation so far which I can consider to be indirectly "happy".
The original (very poorly constructed) question read "Why isn't anyone TERRIFIED or horrified by this apparent underlying theme of Birdman (2014)?" And some comments/answers below were in response to that.