I think one of my biggest issues with Joker (or more specifically, his popularity) and a large portion of his fans is like
Obviously I don’t like how abusive he is with Harley
But every time I explain that to a Joker fan I always get “well yeah but he’s fucking insane so” as a response
But like
a) that’s not an excuse??? Mental illness doesn’t give you a free pass to treat your girlfriend like shit
b) It implies that he’s abusive BECAUSE of his insanity. The mentally ill aren’t automatically abusive, and more importantly, a lot of irl abusive people are not insane at all and are perfectly aware and in-control of themselves despite what they may say
I asked an exbf to explain his obsession with the Joker to me once, and he told me it had to do with his intelligence and how he wasn't as insane as he'd have everyone believe. Which, okay, yeah, Joker is fucking terrifying. He's killed thousands of people, and instead of getting sent somewhere with Death Row, he's thrown into Arkham where the revolving doors release him into society sooner rather than later.
It has been shown numerous times in the comics and shows and movies that he's not as insane as he wants people to believe. He is a psychopath, but he's not insane. I remember Jason calling him out on it once, and Joker was extremely put out about it. But that's where his intelligence is downright scary. He's willing to go above and beyond what is necessary to play the role of this psychopath with no limits, no boundaries, and no rules to follow.
His relationship with Harley is an extremely abusive one. And it's got almost nothing to do with his supposed insanity, and everything to do with power play. He tries so hard to be in control of everything and everyone around him, and poor Harley plays right into that. She's an incredibly intelligent woman (she was a goddamn psychiatrist for fuck's sakes), and that everyone thinks she's some dumb bimbo for staying with the Joker is the real tragedy.
She's emotionally and physically abused by the man she's in love with, and people blame her for it. She fell in love with him while analyzing him, because he is such an intelligent man. They're both highly intelligent people, but she is driven by her devotion and love to this madman, and the Joker is driven to act as an agent of chaos.
What's the scariest about Joker is he knows perfectly goddamned well what he's doing.
And he chooses to do it anyways.
That's not insanity. That's being a psychopath. There's a difference.