The definition of "antifa" is broad enough to compass Dwight D. Eisenhower.

There are certainly people who are Anti-Fascist in the world.

Indeed, there's no such organization. Is this supposed to be some sort of gotcha?

Ha ha, but no, you weren’t. You were told that there’s no such thing as an organized centralized group called Antifa. You were told that it’s an ideological approach to fighting fascism, not a terrorist organization. You were told that labeling antifa as a terrorist organization was going to be an excuse for bringing sanctions against anyone Trump’s administration happens to dislike.

And all of that is true.