As of right now, it doesn't seem that they are mobilizing to try to increase the violence, which I think pretty much everyone can agree is a good thing. Recent (last 20-30 years) has shown that currently, right-wing terrorism is far more prevalent in the US (74% of terroristic murders, according to
NPR).
Many of the recent history right-wing acts seem
exactly like what the worst of the alt-right would encourage if they could get away with it. Even if the alt-right is too new and small for any of those older acts to actually part of their specific actions, it definitely seems like they have a more radical audience to pull from.
Conversely, while Antifa and such has grown this year, I strongly suspect that most of that is reactionary. If the issues they're concerned with were addressed, I strongly suspect most of their new growth would leave. Maybe even the old members, if they felt things were being addressed. If they continued to riot and such, or (god forbid) started amassing a body count, then I would be strongly in favor of addressing them as well.
As of right now, however, I only see one side that is taking uniforms, chants, and ideologies from a monstrous regime. Even if you want to make the comparison between Antifa and the Soviets, I haven't seen any evidence that they want to institute the kind of purges Stalin did.
Don't get me wrong, I'm not advocating for violence here. I have no sympathy if someone like Richard Spencer gets punched, but I do believe that they are adept at spinning that as a recruitment tool. I would much rather limit it, as much as possible, to things like the online shaming and deplatforming. Non-violent is far better when it is possible. Hopefully it doesn't get to the point where we need to actually worry about being forced to abandon non-violent means of change.