I don’t know about that. Writing as an ex-punk, a lot of the punks I knew were pretty non-violent. Not particularly anti-violence, but not particularly violent either.
Although there certainly is a large element of aggression, defiance, and rebellion attached to the music, the fashion, and the lifestyle.
So one other reason for the hatred against Nazi groups was that they provided an outlet for this aggression, defiance, and rebellion. They were an “easy-target”, because everybody dislikes Nazis, and no one is going to harass you for hating them. They were another tribe of young people (the skinheads) that you could exclude from your tribe (the punks, or the SHARP skinheads) and you were 100% justified for doing so.
Relatedly, there’s also a certain amount of self-righteousness to punk, and again, hating on Nazis provided an excuse to be as self-righteous as possible and get away with it. This attitude was quite true of several of the political “crusty” punks that I knew.
These are two other reasons, I think, that can be added to the others mentioned above. Obviously not true for every punk, but definitely for some.
shuffles off to do a zombie slam dance