Performing Nazi salutes has been illegal in Germany and Austria since the end of World War II and is punishable by law with prison time.
If you’re a drunk idiot “jokingly” doing nazi salutes as an adult in Germany, you’re just being a nazi. At best nazi-adjacent.
I think you’re severely underestimating how stupid some people can be without malicious intent. Not that I’m justifying their behavior in any way, but it’s possible they’re just really stupid.
Not for nothing, but it could also be tourists. Not defending nazis, because I would argue that being drunk lowers inhibitions, but it doesn’t make you a nazi.
And I think you are underestimating how much of a deeply ingrained taboo the nazi salute is for the typical German. You are right, some people can be very stupid, especially drunk. But no German who has not been in some way socilized among nazis would be stupid enough to ever casually do a nazi salute. You just don’t do it.
The only exception I might allow besides actual nazis are very stupid or drunk (or both) teenagers trying too hard to be edgy. And even then most people would find it hard to believe that they’re not at least right leaning.