Does it make sense that a lot of people love Batman Begins or The Dark Knight but not both? Do they kind of feel like from different writers and directors or from or with different film philosophies, with BB explaining everything about Bruce's origin and motivations and TDK nothing about Joker's?
I also saw a video that interpreted Joker's hospital scene with Harvey as being another lie/disingenuous from him, just manipulating Harvey rather than being at all sincere about his own views, I think most viewers do think the hospital scene and the interrogation scene as literal and authentic, as being the only times (aside from also the hanging down dialogue) Joker was being authentic.