It's well within any parent's rights to block content like that, yes. If I can prevent my children from seeing obscene and objectionable things until they're old enough to have reasonable conversations about it, I will.
That doesn't mean I want to raise bigots, it just means I want to do what I can to ensure the narratives being pushed on my children are wholesome ones that will help them to grow up to be useful, contributing members of society and parents as well.
Maybe you don't care about that for your own kids; that's on you, champ. I'm not arguing for anything censoring anyone else, or anyone censoring what any adult reads.