What is funny? What is humorous?
Generally something that doesn't fit, something that looks surprising and out of place.
All the jokes and funny scenes and whatnot based on this.
But not everyone find the same thing funny. We might find one thing uncomfortable or unnerving, while others still enjoy it. Sometimes society, societal norms (other people) place pressure on us to don't find stuff funny. But people aren't wired that way, so when they find themselves in a situation where they find something funny, but the public discourse around the topic makes it taboo to laugh at it, these people feel shame, then anger, and they lash out to others who they think made them feel ashamed: those who made the joke, or were witness the same scene and were able to laugh despite the outside pressure.
Example.
Imagine a video of a kid on his plastic toy bike rolling down a small hill. He can't stop and rolls into the drainage ditch on the side of the road and flops. This is a classic funny cute kid doing some stupid shit video. He doesn't hurt himself since all grass there and whatnot. We all fell when we were kids, still grew up. It's fairly innocent.
Some might hypocritically start judging others to find this funny. But some can get really mad about this. And it's the public narration is the fault, these days they made kids into holy cows, and it's projected that we mustn't find such things funny. In their effort to appear the most rule abiding, some people make an effort to "regulate" others, how they behave, what they say, what they think.
Such cases.