You've missed the point. Namely: If one person's semi-trollish advocacy of monarchy under a pseudonym several years ago means he's too dangerous to be allowed t

You've missed the point. Namely: If one person's semi-trollish advocacy of monarchy under a pseudonym several years ago means he's too dangerous to be allowed to speak at a tech conference, then surely other people's absolutely sincere advocacy of Communism under their own names, today, would make them even more dangerous, and they should also be barred from speaking... right? If not, why not?