If I own a bar, and you, a patron, start threatening people (prohibited speech), should I have the power to (pre-emptively) have the bouncer toss you out? Or should I be forced to take only "post-fact" measures, and just stand there and let the brawl happen and wait patiently for police to arrive?

To me, it seems more ethically problematic to allow immediate threats of violence to proliferate on a platform unchecked until it can be proven that violence actually occurred, simply for the sake of ideological purity.