@akareilly great points, and for those that would use the violence as a tool for victim blaming, allow me to add this:

It takes a surprisingly low amount of violence to keep an asshole out of a space. As a bouncer for several years, I maybe had to use physical violence only three times, and nobody ever went to see a doctor for it. A little reminder that being an asshole can have consequences is pretty far from a death penalty.

Point being there's no revenge whatsoever indeed, the job is just to avoid harm.

And the better society does at keeping abusers away from their victims, the safer even the abusers are. You're doing them a favor by banning them.