I think that what he is wearing is inappropriate at the Olympics for official practice sessions. In the official portion of the Olympics, including practice sessions, he is specifically representing his country, and should be seen to be doing so. Outside of the official sessions at the Olympics, even while he is at the games, it would be OK, I think.
I am actually surprised that so many American posters on this board think that this is OK. To me his behaviour shows that he either does not realize what an honour it is to represent his country at the Olympics, or else he is simply not thinking at all (probably the latter). I am not American, so this is not a patriotism thing.
To me this has nothing to do with wearing something Russian as such. It would be just as inappropriate, IMO, to wear something Japanese or Canadian in the practice sessions.