OK, as much as I like the idea of Nazi scum getting their butts kicked in principle, I'm going to have to reserve my praise for now, because this communiqué is lacking some important details, and in practice it just isn't that simple.
The mandate that 'if somebody is threatening to kill you, you must kill them first' is widely respected by those who don't consider violence to be unjustifiable under any circumstances, but it's sort-of predicated on the threat part. While as a queer, crazy Jew-of-mixed-ethnicity with multiple hereditary/congenital physical and neurological issues, some of which are potentially disabling, I would have to say that I myself consider the very existence of these jerks to be a strongly-felt potential threat to mine; but, on the other hand, both from an anarchist and a simple pragmatic viewpoint, I have to recognize that being a Nazi, moderating an online forum for other Nazis, unsuccessfully planning a protest against a local Pride march, etc. are not, in and of themselves, exactly the same moral valence as, say, pulling a gun (or chain or whatever), making a verbal/written threat, or even standing around being menacing.
Your average anarchist, or any other sort of person who values civil liberties, would denounce prosecuting anarchists for murder on the basis of their support for attentats/'propaganda by the deed'. We'd like to think, and certainly hope, that that support and its various verbal/written expressions pose a real threat to capitalism, the State, and authoritarian structures; but it's not the same as pulling a Czoglosz. Hence the whitewashing of Sacco and Vanzetti and the continuing controversy about their guilt.
Also worth considering is the fact that racist thugs are generally reviled as much for committing acts of unprovoked violence as for being racist thugs. Beating jerks up can send a message to other jerks, but it makes it really easy for less-obvious jerks to cast aspersions on you. We may lionize the tough Commie/socialist street-fighters who went around picking fights with the original Nazis now, but back in the day they were a threat to public order (not that I have a problem with that, but it made it a lot easier to ignore the nastiness of the people they were fighting with).
On the other hand, a beat-down is more or less justifiable in the eyes of the public if it comes close on the heels of something that constitutes a fairly real threat and/or offense, or if the person getting beat is a habitual threat and showing signs of their typical antics. So, I have to ask: Was he known to use 'counter-protests' etc. as a prelude to thuggery, or just generally violent? Is the local racist thug scene particularly given to violence, especially in the recent past? Is there a pattern of this kind of thing happening?
And, probably most importantly: did he get his arse kicked *on the day of the march*, while waiting vainly for his little friends? There's justification for beating interlopers up for trying to ruin events and disrupt 'safe space'. It's not the kind of thing that's universally laudable, but it's enough for me. On the other hand, if the interloper fails miserably in his enterprise and you just go and beat him up for trying, especially well after the fact, it's kind-of overkill. Better to just let him take care of looking like an idiot and save your energy for next time, IMHO.
Anyway, sorry to ramble, but it'd be nice if you filled us in on the circumstances.