> I've also saw more than one person disown their parents after being sucked in to the anticircumcision movement - men who had until that moment seemingly normal lives but were then convinced their sex lives would never reach their potential because of a decision their parents had made....

That's a really good point. Before the internet, and especially social media, people had weird and arguable toxic ideas, but it was almost always impossible to form a geographically-based community around them, so they'd almost always peter out and their effect was limited. The internet broke geographical limits, allowing intense purely ideological communities to form around almost every idea and validate them, no matter how wrong and misguided. In our very online times that can have serious social consequences, sometimes for good but often for ill.