I don't think the director was trying to "own the incels". This feels like a on purpose bad movie to spite Hollywood execs like Freddy Got Fingered. My take is
>first movie had no budget and studio had no faith in it
>became a massive hit
>suddenly studios are sucking directors cock
>mainstream media tries to politicize the film
>leftist claiming its a chud right wing movie, right wingers projecting onto it
>director did not want to make a sequel but studios insisted, throwing massive amounts of money at it
>dude goes all out with draining the budget, bigger sets, musical numbers, lady gaga
>movie itself is a commentary on how the character of the joker is romanticized when in reality he;s just a mentally ill man that receives no help
>every interaction between Harley and Joker is a musical, showing how she's romanticized their relationship
>part of the movie where Arthur breaks down with "Stop singing. Just talk to me"
Granted I don't think the movie is good but I don't think it was meant to be. I think this was just an attempt to fuck over the studio and drain their pockets.

Also all the people who actually wanted a sequel to the first movie and have it spin into some kind of origin story for a joker cinematic universe are retards. The fact you had people expecting this version of the joker to beocme some kind of crime boss and fight a guy in a bat suit is insane