Do you want your kids to be indoctrinated into a fundamentalist religion without your knowledge? No? Then you might want to give other parents similar choices with their pain points, no matter how much you disagree with them. Parents keeping teenagers away from Internet or whoever their crushes are is bs, that's another story. But in general the problem is that there are too few categories, not too many. For younger kids let 3rd party repositories maintain their own and let parents opt in to ones missing from official Gnome.