Teaching kids to be responsible about their online activities is good, but it can’t be the only solution. Just like teaching women to be wary of men can’t be the only solution to stop date rape. (Also, making the victims responsible for stopping their own victimization doesn’t really work anyway, particularly when it comes to kids. It just saddles them with tons of guilt if they fail to stop it, which can be used to keep the abuse going)
I don’t see why it’s such a problem to have billion-dollar sites aimed toward kids being required to hire adequate moderation if they have social services available. No age checks needed, no verifications or anything, just clear and very strict rules (because again, this is aimed at kids, if adults want to use it they can conform to the kid rules or gtfo) that get enforced across the board.