Why use a pronoun at all? Why not use the noun "USSR"? It always freaks me out a bit when people use "we" to describe e.g. a team they supported in a sports game. Feels a bit strange to give up one's identity like that.
(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Although, I suppose for a work of historical reference, they should be taking a more neutral tone, but we're a pretty proud people :)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.
Now, the question just remains as to which people get to be counted in that "we". Here, I'll move back to your sports team comment. The players obviously have the right to say "we won", since they were out there scoring points. The coach, however, was not. Does he get included in the "we"? How about the athletic trainer who fixed up the star player after an injury. Does he get to count himself? The team's owner didn't score any goals or pick any plays. Her contributions were far more abstract and mostly economic. Does she count? How about the station who paid the owner for the broadcasting rights? It's more nebulous and economic than the owner's claim, but still largely the same.
If the TV station seems like a step too far, imagine that it wasn't a soccer game, but rather gladiatorial combat that they were paying to broadcast. If someone at the station said "We killed fifty prisoners this evening", would you correct them that they hadn't actually killed anyone? How about the network's sponsors? Or the audience? They'd have just as much involvement with the prisoners being stabbed as they would with the goal in the soccer game. If they shouldn't identify with their minor part of the glory in the goal, why should they have responsibility for the other?
I find nothing weasel-like with stating "Soviet engineers created the F-1 nuclear reactor in...". It's perfectly accurate. Saying "We created..." is rubbish. I mean, are you suggesting all Germans shouldn't be bothered saying "we killed 6 million Jews in the Holocaust"? Is that less frightening that the alternative "Hitler's regime killed 6 million Jews in the Holocaust"?
I think your examples are contrived. The coach/trainer/owner says "We did it!" as a shortened colloquial form of "we achieved our goal of obtaining a victory!". I'm talking about people who sit on the couch watching a game, who have never attended a match or contributed anything to the team they 'support', and say "we won". I'm not saying there's anything bad with that, just I find it strange. Many of my closest friends do it and I tease them for it - just like they tease me for only being interested in the team/individual performance/strategy.
All I did was point out that people seem to (conveniently) identify with "we" when it reinforces a positive self-identity and some people choose not to identify when it reinforces a negative self-identity, which does make me wonder how healthy their identity is as a consequence, and I personally find the consequences of this unappealing.
Sure this can be mostly harmless e.g. in the case of sports, but it is identifying with a group psychologically and somewhat irrationally in my opinion and it's something I don't find natural.