Heard from @TeamYouTube about age retristricting the bath challenge video:
in short, kids might see it and repeat it and they don't want people to get hurt.
I don't want people to get hurt either so, sure. I'll deal with it.
Seems hypocritical and unfairly enforced. But OK.
Clearly the thing to do is find all similar videos and claim to be a parent, saying your kid got hurt copying the video. If they won't enforce their policies fairly, force them to do it.