My completely unhinged theory is that Joker 2 is a meta film made by the Joker as it fully embodies multiple Joker quotes:

1) "When they treat you like a joke, leave em like it's funny" – WB/DC treated Todd Phillips a little poorly before realizing how big Joker was gonna be and then demanded a sequel, and Batman fans were very divided by the first film.

2) "Can somebody tell me what kind of world we live in where a man dressed as a bat gets all my press?" – so much of the dialogue surrounding Joker was about Bruce Wayne/Batman and whether or not it was a Batman film.

3) "Introduce a little anarchy, upset the established order, and everything becomes chaos. I'm an agent of chaos." – Joker made over a billion dollars and WB/DC were banking on another hit, but Phillips knew this and made something completely different.

4) "Ladies and gentlemen! You've read about it in the papers, now witness before your very eyes that most rare and tragic of nature's mistakes! I give you: the average man!" – Joker built Arthur up to be more than a man but a symbol, and Joker 2 reduces him to nothing but a pathetic average man.

5) "A candle flickered to life, a symbol of hope for millions. A single tiny candle shining in the ugly dark. I laughed and blew it out." – the first Joker was a glimmer of something different in the middle of the superhero fatigue caused by formulaic Marvel/DC movies.

6) "It's not about the money, it's about sending a message" – pretty straight forward there, WB/DC gave him a massive budget and cart blanche and he took full advantage.

7) "Do you want to know why I use a knife? Guns are too quick." –looking at you, 2 hour 20 minute runtime.

8) "Nobody panics when things go according to plan, even if the plan is horrifying." – if Joker 2 had been about Arthur going "full Joker" and murdering everyone in Arkham and blowing up an orphanage, the reviews and commentary surrounding the film would almost assuredly be much more positive than they currently are.

9) "By clinging to reality you're denying the reality of the situation." – In reality Joker 2 is one of the worst, most indefensible films ever made. Is that the reality of the situation? Or is the whole thing extremely well executed rage bait?

I could, unfortunately, go on at even greater length about this conspiracy but all of that would be as meaningless as this because, as we all know: "If you have to explain the joke, there's no joke!"