When the Crips fight the Bloods, nobody says "If you're not a Blood that means you're with the Crips. If you hate the Crips that means you're a Blood." If someone actually does say it, nobody takes it seriously.
When it is Fascists and Antifa on the other hand, people actually believe that absurd "logic".
I know I know, Antifa only means "Anti First Amendment", no it means "Anti-Fascist". Because their name says they are anti-fascist, that means they are anti-fascist, just like how National Socialists are not Socialists because their name was propaganda and a lie, just like how the name "Antifa" means they are anti-fascist. And of course they have no beliefs other than opposing fascists, which is why they oppose so many other people above and beyond fascists. They have no central ideology except they do but you can't call them on it because they give themselves a name based on what they oppose instead of what they support.
Also because there isn't a club charter and membership list, that means Antifa doesn't even exist in the first place, except for all the various organizations that do exist under the Antifa banner.
If you don't like it when Antifa gets violent, somehow that means you don't like it when the protest peacefully. If they actually do that is. Because opposing violence means you oppose everything else about them. If they see people waving banners, and respond by waving banners, I wouldn't have a problem with them. I never see that. If you punch someone for waving a banner, you're the bad guy.