Lets all not dance around it, people never wanted to give the movie a chance...simple as that.
From the moment it was annouced, people were hellbent on ripping into it.
Be it for comic accuracy that otherwise doesnt matter much, to the trailers being a problem for not showing enough(which normally seems to be a problem, looking at the reaction to the WW84 trailer in terms of "oh i already can tell the whole plot thanks to the first trailer"), to the fact that it dares more which is now a problem when before people were complaining about how that should be the way.
People were falling over their feet to drown out all criticism about the joker movie, that comic book movies shouldnt be 100% accurate, should try different things and so on.
But here suddenly 100% comic accuracy is a must, otherwise its ****?
People were from day one against the movie for the sake of it, without willing to give it even a tiny chance.
So far most reviews tell you that clearly, that those who gave it a chance...were positivly surprised by how well they nailed the characters and all.
The same can be said about Joker though. Plenty of people did their best to bring it down. BOP couldn't find a target audience and I think that the R- rating definitely contributed to that. Reminding fans of Suicide Squad and Schumacher Bat films probably didn't do any favors either.