I don't understand how volunteer, non-sworn officer, non nevada licensed security guards (volunteer "goons", who are just private citizens at a private event in a public convention center) can use physical force to take a non-violent trespasser off stage without exposing themselves personally and their organization to substantial liability. Not super familiar with Nevada law.
(Obviously doing crowd control, providing information, and front line emergency response is absolutely fine, although tbh even that they should probably have guard cards in most jurisdictions for liability reasons. If someone is violently disruptive, as a private citizen go for it, but unauthorized speaking on stage is pretty far from that. Would be hilarious if dude makes more money from that than he was stiffed by his employer.)