Yeah I hate talking to fans of that movie, and I'm a fan of that movie! As a person with a mental illness or three, I think the movie has a lot to say, but it feels like 7 out of 10 fans are going to tell me that what the movie has to say is that the Joker was right all along and somehow they'll have no strong takeaways with regards to treating others with respect and dignity regardless of their situation or "otherness". Or about the dangers of becoming what people fear you are.

They just kind of think that the mental health system failed Arthur (correct!) and he had no choice but to do what he did (incorrect).