The problem when you own a space that if you let certain groups of people in, such as, in this example, Nazis, you'll literally drive everyone else away from your space, so that what started off as a normal, ordinary space will become, essentially, a Nazi bar.

It's not only Nazis — it can be fascists, white supremacists, meth-heads, PUAs, cryptocurrency fanboys — some groups will be so odious to others that they will drive everyone else from your space, so the only solution that you can enact is to ensure that they don't come to your place, even if they're nice and polite and "follow your rules", because while they might, their friends won't, those friends have a history of driving away other people from other spaces.

"you have to nip it in the bud immediately. These guys come in and it's always a nice, polite one. And you serve them because you don't want to cause a scene. And then they become a regular and after awhile they bring a friend. And that dude is cool too.

And then THEY bring friends and the friends bring friends and they stop being cool and then you realize, oh shit, this is a Nazi bar now. And it's too late because they're entrenched and if you try to kick them out, they cause a PROBLEM. So you have to shut them down.