Speech is violence, and silence is violence, so if you say or do anything we disagree with, we're justified in attacking you until you're silent, which is also violence, and we can attack you some more.
I really don’t know where the guy was going with the "when is the window for someone to wear a Halloween costume" nonsense. It obviously was a Halloween costume, but even if it was the middle of February, you still don't get to assault someone because you don't like their clothes.
What's actually funnier is that the ONLY reason they felt comfortable assaulting the guy isn't because they thought they stumbled upon a German WW2 soldier at a college bar, it's because he's just skinny college dork with an edgy costume. If it was some skinhead dude with swastika prison tats, they wouldn't say a fucking word.