AntiFa is going to be a problem in opposing the so-called President. This group will be the convenient and easy excuse for him to justify selective crackdowns and moral equivalencies. Please note that AntiFa assumes in advance that their opponents are violent - in other words their opponents, they assume, typically the alt-right or worse, have ALREADY been violent and deserve a physical confrontation.
Now I understand that the KKK and neo-Nazis actually exist to HARM others and that AntiFa claims to exist to DEFEND, but that defense is not guaranteed to be within the bounds of legality if their definition of defense is to "disrupt" alt-right rallies for example.
Of course, all this is EXACTLY what the alt-right wants them to do so that they can say that the left wing is the real danger to the US. This scenario is not unlike Al Qaeda hoping the the US would attack in Iraq so that they could promote the narrative of the US being at war with Islam. And AntiFa will deliver in this case to the alt-right. Let's not encourage this movement.