This is why “hate speech’ laws are overtly unconstitutional. You simply can not (Constitutionally) criminalize mere speech.
As for Russia is waging a war of aggression. It certainly looks that way to me, but as of now I am unaware of any place where the question has even been adjudicated, let alone decided. So Fritz is jumping the gun if that's his excuse.
And by the way, there is no legal prohibition against insulting people that I'm aware of. If there were 90% of us would be in jail, yes? 8^)
Well, for Germany he actually has it the right way round. And yes, the German Criminal Code expressly states that insulting others is a criminal offence. German judges would have a field day with those sovereign citizens you see on YouTube calling coppers every swear word in the book and flipping them off :-)
By the way, i was wrong about the incitement. That`s illegal, of course, but it`s enough to show approval of a war of aggression to be on the wrong side of the law. Wearing the “Z” symbol probably could be seen as approval.