Antifa isn't real.

Of course it isn't. Just like critical race theory isn't real even as it's being taught at colleges and universities (and effectively at lower levels of education as well though typically not under that name because parents have caught on). Or SJWs aren't real despite the fact that it's just a descriptive term for a certainly real type of person and it doesn't matter if someone self-identifies as one or not.

Regressives have often used such denials. They know something that can't be named is something that can't be fought against, and that control over language is a powerful weapon.