As a society, we're responsible for all our children. The point of child protection laws, and population protection in general, is to support and protect them, because often times, parents are incapable of doing so, or it's social dynamics that most parents can't really understand, follow, or teach in.

Yes, parents should teach and protect their children. But we should also create an environment where that is possible, and where children of less fortunate and of less able parents are not victims of their environment.

I don't think demanding and requiring big social platforms to moderate and regulate at least to the degree where children are not regularly exposed to life-threatening trends is a bad idea.

That stuff can still be elsewhere if you want it. But social platforms have a social dynamic, more so than an informative one.