Technically speaking, there's no law governing any history; There's laws governing behavior in the present that arose from events in history. I live in Germany for 12 years by now; I can't claim a lawyer-level knowledge of e.g. §130 StGB, but I have a basic understanding.

What I'm having trouble following is the logic of "the violent extremism on the other side is less bad, because it hasn't led to similarly horrible effects yet".