ANTIFA is an unorganized ideology. It quite literally means anti-fascism. Therefore, if you are opposed to ANTIFA then you must favor fascism. Since ANTIFA is unorganized and has no leaders or members, it's convenient for fascist Trump to designate this imaginary bogeyman as a terrorist organization. But MAGA cultists believe that ANTIFA is real, so it works for Trump to claim anyone he dislikes as a member of ANTIFA while no one can prove they are or are not ANTIFA. It's a good fit for Trump's fascist takeover of American democracy. Trump must be a genius, albeit an evil one.