(Full disclosure, I'm a Russian living in America, lived here for 18 years now and I still sometimes say "we" when speaking about things the USSR has done.)
Although, I suppose for a work of historical reference, they should be taking a more neutral tone, but we're a pretty proud people :)
Even the whole supporting a team thing seems strange to me. When watching a sporting even I applaud individual players regardless of the team, and make comments about the team strategy and overall game, but it's not that important to me who won other than how it will affect the interestingness of future games. Supporting countries is even stranger because it just all feels so tribalistic.
I've noticed no such thing- people seem to say "we" in both cases in the majority of times, in my experience. They often take losses to heart very strongly.
Even the whole supporting a team thing seems strange to me.
There's nothing wrong with that, but honestly, if you're starting from such a point of being unable to relate, it isn't worth examining in much deeper detail.