As a parent, I can tell you that my son is exposed to these things all the time. I cannot block every possible word or string of words to prevent my son from finding these sites. At the same time I cannot control what others, and neither can site administrators, say in comment sections on youtube videos and the like. Theories are everywhere, like opinions. I don't talk much about the things I read although he sometimes hears things my wife and I discuss. He's got some mixed and conflicting beliefs and most of them stem from things he read online.
If he talks to me about these things, I try to be objectionable and listen. I also try to explain my beliefs on the subject. At the end of the day, his beliefs have to be his own, whether I agree with them or not. I do, however, worry about some of the subject matter he's exposed to. Yet, if I tell him not to visit those sites or read about that subject, that's exactly what he's going to do. Now, if only I could use that logic to get him to do his homework. No, I don't encourage my son to come here.
The modern definition of ‘racist’ is someone who’s winning an argument with a liberal.