Why wouldn’t I be? It’s my platform. My right to express myself is just as valid as anyone else’s. Banning is a form of expression, is it not?

Edit: I just realized that I totally misread your comment, so the rest of this thread probably doesn’t make sense. For some reason I though you were saying that I should not be allowed to ban people on my platform but you actually said the exact opposite. Sorry about that. To answer your actual comment:

The question is whether or not you should ban people you disagree with.

Well, that’s my decision as the platform owner, isn’t it? If I decide that Nazis don’t deserve to use my platform, I kick them off my platform. I don’t see any dilemma here.