If you've never come across these types of memes that edgelords post where they attempt to highlight the inadequacies of "the masses" in a bite-sized meme form, then you can see a pretty great example of what that is right here.
If you're wondering what a comic book villain has to do with this meme, a lot has to do with the fact that the Joker's anarchist tendencies have long been an icon of counter-culture for people who fancy themselves outsiders.
This could probably date back to Heath Ledger's Joker's monologue about social norms that he gives to Harvey Dent when he was placed in the hospital after getting half of his face burned to a crisp. You may remember the scene as Harvey hilariously doesn't recognize the Clown Prince of Crime until after he removes his surgical mask.
The Joker tells Harvey after this wonderful moment: "You know what I've noticed? Nobody panics when things go 'according to plan.' Even if the plan is horrifying! If, tomorrow, I tell the press that, like, a gang banger will get shot, or a truckload of soldiers will be blown up, nobody panics, because it's all 'part of the plan.' But when I say that one little old mayor will die, well then everyone loses their minds."
Joaquin Phoenix's performance as Arthur Fleck, a disturbed, beaten-down grown man who lives with his mom, hallucinates having a girlfriend, and dreams of becoming a stand-up comedian, struck a chord with some people. Arthur eventually has enough with the "meanness" of people and society in general, and the dumpster fire that is his life culminates in him murdering a late-night TV show host who brings him on to make fun of him after he bombs (the non-violent kind) in a comedy club.
Arthur's monologue at the end of the film before shooting the host (Murray, played by Robert De Niro) touches on a similar social discourse:
Joker: "How about another joke, Murray? What do you get when you cross a mentally-ill loner with a system that abandons him and treats him like trash? I'll tell you what you get. You get what you f***ing deserve!"
