I do believe it's from Starcade (due to the background). A JonTron series on Star wars games. He does a huge amount of quick gags. He's a pretty funny guy. Lots of memes made from his content.
Joker was really close to being a great movie, but was ultimately too confused about what it wanted its message to be. Unless the message was just "I'm fed up, let's get violent already".
That's the problem, it didn't have a real message. It was aping Taxi Driver and King of Comedy, and it copied the aesthetics of those films very well, but it was all superficial. It's a perfectly fine movie, but The Batman had deeper social commentary than Joker.