It's not the Community Guidelines, it's for YouTube Partners that are
selling advertisements on their videos as YouTubers. This has always been a part of the YouTube Terms of Service; it's just more publicly known now.
Nobody's reporting on it legitimately (just a bunch of biased hype / scare nonsense), but the jist of the situation seems to be that family friendly advertisers don't want their advertisements on controversial videos again.
Because YouTubers aren't using accurate tags and metadata during upload, YouTube can't filter the ads properly, but YT knows they can't rely on all its users to learn how to do that. So they're trying to update the algorithm to figure that out itself now and are going nuclear on the videos it finds until they get it right.
But of course, everyone is freaking out because they're a bunch of fanfags that need to protect their precious little senpai, who are too dumb to understand that YouTube's ad income is where their favorite YouTuber's ad income comes from. Lord.