> Should it be legal to tweet a sieg heiling dog in Germany, when it's your dog, and you taught it to sieg heil, and you filmed it at Auschwitz? Or what's the exact boundary between acceptable and unacceptable?

Yes? Yes, of course? Being an idiot on internet has traditionally been legal in civilized liberal western countries. Such person could be banned by a platform that doesn't want such content and ostracized by their peers (they guy who made sieg heiling dog video claimed he did it for his girlfriend or something and I would dump him, if I was her) but I don't want my government to build a panopticon to prevent such behavior and I don't want my taxes wasted on policing it.

In Germany it's illegal to venerate the Holocaust in any way whatsoever — for obvious reasons. Are you suggesting that should change?

Yes, absolutely. It should be perfectly legal to venerate whatever people want to venerate, that's basic freedom of conscience.