What's frightening about Joker is it's impossible to tell whose side we're supposed to be on. I suppose that's one of the many definitions of compelling art, but it's also cowardly. The official summary of the movie describes it as a "cautionary tale," but it's unclear what that refers to. A cautionary tale about mental illness? About not ignoring those who feel beat down by society? About not handing guns to people with laughing disorders? But it's undeniable, at its climax, when he is at his most despicable, that Joker does look kinda cool, or at least is framed that way. What are we supposed to do with that?
There's so much about Joker that's downright nasty, and not in an entertaining way: The fact that the movie speaks, intentionally or not, to incels, those who believe in the oppression of women and minorities and in taking whatever they want with physical force. The fact that, just seven years ago, a man dyed his hair and shot up a movie theater during a midnight screening of The Dark Knight Rises. And that's saying nothing of the mental illness angle, which Fleck uses, multiple times, as an excuse for his behavior.
In a way, the Joker is right: He's been abandoned by everyone, and the only way he can get attention is through violence. If the world had just been nicer to him, the film seems to say, if only he'd gotten the right help, if only he hadn't been mentally ill, if only the woman he loves (read: stalks) had loved him back, things might have gone differently. Yet it also conspicuously ignores the narcissistic conviction that defines this kind of person; that the world doesn't care about them, and that it's up to them to make it care. When Gotham finally goes up in flames, descending into the chaos we all know it must, it's Joker the film zooms in on, Joker it cares about. It's a complete power fantasy (and, due to the ambiguous ending, could literally be one).
Should we pity these people? The best villain narratives usually are quite sympathetic: Anakin Skywalker became Darth Vader because of heartbreak and what he saw as betrayal. Daenerys Targaryen watched the only friends she'd ever had executed one by one at the hands of those she hated most. But Anakin also killed a roomful of schoolchildren; Daenerys crucified people as a political statement. There's nothing in Joker to remind us that what he thinks is wrong. The movie isn't badly made or even ugly to look at, but there's a mean, smug little heart at the center of it that, at best, irresponsibly frames a familiar male power fantasy as a revolutionary act. And that's not funny at all.