I'm sorry but some of your questions got jumbled in translation. I'm not sure what you mean by how them call.
The reason I find them polite is just how I see them interact with teachers and students, and me in particular. Nothing over the top, just fairly generous. If anyone in class has forgotten something, needs paper or what have you they're the first to offer. If someone is being rude, they're the first to comment. If I had to judge the Russian people based on them I would conclude that Russians are generous people with well defined values. I'm sure you have your share of jerks as well, but I'm fortunate enough not to have met any of those yet!
I hope all this translates well!