Yeah, Yarvin is a genuinely highly controversial figure who's one of the leaders in neo-monarchist and neo-reactionary philosophy. One could imagine there being controversies like this about him 20 years ago, before the current political climate. He knew what he was getting into.

The others are basically just people who were unfortunate enough to be saying the "wrong" thing in the wrong place at the wrong time.

His philosophy is crazy and most people consider it either laughable or offensive, but he was supposed to be giving technical talk about Urbit, so I don't see a reason why his philosophy should matter in that.