This did happen to Glock9 for violence. He had an opening montage for his current series and was demonetized for violence. The timestamp referred to his opening at the point where he punches Arlene in the face. They demonetized 3 or 4 of his videos for that. I guess screwtube doesn't know the difference between violence against women and violence against zombies. I mean, zombies are people too, right?
You have to understand that most of these things are done by algorithms, and those can be tripped for really weird reasons. Even when they say they have "manually reviewed", they actually have not. I have a single video demonetized in my library. Apparently it has "excessive swearing" in it, as confirmed by YouTube's manual review.
Except, it's a 30 second short, where I've gone over it with a finetooth comb, forward and backward, and there's no excessive swearing in it. There's actually no swearing in it at all (It's extremely rare to ever hear my swear, due to my kids watching them).
But despite this, YouTube in their "manual" review finds excessive swearing, where there 100 % is none, nothing even close to it, no aggressive language, nothing that could remotely be taken or mistaken as rude. Now it was a Shorts video where I happened to get killed by zombies, so if they had said "violence" I could have understood it, though peculiar still as it's just a video game, and death in video games doesn't normally cause any issues.
So knowing WHY a video was demonetized is super hard.
I do think people will have to be more careful with the opening bits of their videos, ensure cleaner language, trying to avoid excessive violence... and hope this whole thing blows over.
What I find more weird though is that "all" swearing/curse words are seen as equally bad. "@%$#" and "crap" is now a curse, which I personally would not consider it. The worrying bit is that they'll expand the vocabulary of "cursing" even more, making it very hard to actually describe something "This game runs like @%$#" caused demonetization ... so you'd be saying "This games runs sub-optimal below the acceptable range" or something else, which is dumb.
But that's YT!