>But I must beg the question, if society normalizes and encourages violence against Nazis, doesn't that mean that calling someone a Nazi is a potentially serious act? And, what if they aren't really a Nazi?

Context is important and it seems like you are trying to blur that context for the sake of an argument. "Mitt Romeny is a Nazi" is not a serious opinion. "Punch a Nazi" is only a slightly more serious notion, but there is firmly a tongue in cheek aspect to it. There is a reason why the only "punching of a Nazi" to reach any type of penetration into pop culture was from the year before this Kickstarter was launched. This comic is not a serious threat anymore than your average issue of The Punisher.