I'm not sure neo-nazies (and no I'm not going to beat around the bush and call them alt-right but call them what they so clearly are instead) make enough of the population to warrant a counter-protest. Maybe it just draws more attention to them. Of course if I'm wrong (I would not have predicted a Trump victory either, so maybe I'm not so good at such mind reading) and hate marchers and their sympathizers actually ARE a significant portion of the population, then heaven help us all, and we are in trouble regardless of counter-protests.
I'm sympathetic with those who counter-protest, I know they are fine people doing it for the right reasons, I'm just not sure it actually doesn't give some small minority of openly hateful people more attention than otherwise.