Alternate title: Are Antifa (anti-fascists) right?

So then, storytime first. I've encountered an Antifa supporter in real life (friend of my roommate)! After some introductory chit chat I noticed he seemed quite radically left, so I asked him to talk about what he thought about Antifa and I received a glowing review of the movement.

I'm not a massive fan of what Antifa does, so I asked him why Antifa think they can go around punching people. His answer came in two parts.

The first part of his answer was him clarifying that they only ever preemptively hit self-avowed Nazis. I told him I knew of reporters and peaceful (non-Nazi) right-wing protestors who weren't Nazis but still got assaulted. He then told me 'We don't get it wrong, they may not say out-loud that they're Nazis, but we can tell if they are'. Buoyed by the look of confusion on my face (I was thinking 'is this guy for real') he continued onto his second point.

He said the reason that they can punch Nazis (or anyone else who they label as Nazis) is because of the institutional power they possess. In other words, the Nazi scum may not be causing any actual harm to people, but they still causing harm to the people because of the 'institutional force' that the Nazis wield.. That's why its OK to preemptively punch 'Nazis', since its not preemptive at all if the Nazis have been wielding and using this 'institutional force' this whole time.

I did attempt to explain the 'harm principle', the difference between what constitutes actual physical harm and what just constitutes hurt feelings, and because of this, I told him that a response of physical violence against someone who hasn't already done the same isn't valid (I stopped short of calling it 'childish').

It seems to me like there's no real neo-Nazi threat (or if there is, its size is greatly exaggerated by Antifa). I think it's just a bunch of angry radical leftists, pissed off at having Trump run shit who promptly decided that political violence is a fine way to manage their anger.

Thoughts on this? Antifa's use of force or just thoughts about Antifa in general?