They haven't marched yet; the majority of marches are today. We're much more worried about their disruption by Trump supporters and their use as a tool who just want an excuse to break stuff, honestly. That's probably what happened in Portland in the first days after the election--there's a certain amount of suspicion that the people breaking stuff didn't vote for Clinton, possibly didn't vote at all, and are just anarchists looking for an excuse to participate in behaviour that they believe will break down society. I knew people in college who were that sort at the WTO protests in Seattle at the time. I agree that it makes the movement look bad, and so do my friends--with one or two exceptions, who believe a little social breakdown is necessary to enact change. Which, you know, that's a conversation I'm done having.
I am still okay with that guy getting punched, at least a little, because literally neo-Nazi. Apparently even his awful haircut is intended to evoke his politics, and he was talking about them at the time it happened. It's hard to be upset when someone punches a Nazi, even if it doesn't do any good for the movement.