For those who are leaning toward joining a white-supremacy group, because the more the idea is forbidden, the more attractive it is. If you block that link, you alienate these boys a little more as you appear to be the enemy, dominating them by telling them what to look at and what not to look at. They'll see you as another arm of the establishment telling half-truth at best. You'll make the white-supremacy movement look more attractive and gives these white boys a final boot in that direction. I'm no fan of censorship, especially governmental censorship.
Government is in people's lives enough already.
There is an answer but it is not easy. We need a different school model. The schools teach children to be quiet and powerless and not to think their own thoughts. As communication among children increases with this technology, the clash between the children and the established adult world of pecking orders and lies will become more abrasive. The situation is that the children are born right and we make them wrong.