hmm... Russian tourists — I can’t say I’ve met many of them, but they did not seem rude to me. The German young tourists were rude, the elderly folks are diametrically opposite — exceedingly polite
It isn’t so much rudeness as an obnoxious boisterousness. They remind me of a sixth grade class I chaparoned when my children were small.
I’d never do that again!
Germans are just very curt. My family was German and I retain a lot of that very curtness which I think some see as rude.