Who is making these rules about what jokes can be made, and by what mechanism are they enforced? I've never seen anything about that.

There are social consequences to making certain kind of jokes. Like there always have been? But which kinds of jokes and what sort and degree of consequences are changing.

You can have an issue with that and resist it, but the mechanics of this institution are not new. These unspoken rules about who can say what and what will happen if you transgress them are the invisible infrastructure of social connection and ultimately society. The rules are changing fast and by different players than is traditional, but the fact that there are rules and consequences for violating them is as old as us.