For this question, let's take the theory aside that …
… the whole story of the movie might only exist in the Joker's mind and doesn't reflect actual events.
In the "Joker (2019)" Thomas Wayne is portrayed as a successful business man, who
- … does treat people from a different degree badly
- … think it's the people's own fault if they are poor
- … seems to run for mayor only to increase his power
And at the end of the movie …
… he gets shot by a masked robber on purpose who says:
"You get what you deserve."(1)
I early DC/ Batman movies Thomas Wayne is portrayed as a successfull businessman as well but also as someone who seems:
- … friendly to all kinds of poeple
- … to use his wealth to help to make Gotham better for everybody
And most importantly:
… is shot from a "random" robber, who might not even have known who he was – and not on purpose.
Especially the last point was - at least in my opinion - very important for the transformation of Bruce into Batman.
So how does the the portrait of Thomas Wayne go along with the actual comics and/or Batman and the DCU?
I also found this article “Batman”: Why is Thomas Wayne A Meanie Now? which tries to address this question as well. But it's really not satisfying.
(1) I might be paraphrasing, if you do know the exact quote, please edit it into the question.