Root for USA. Root for Canada. Root for CBJ players. Root against Ovy/Crosby/whomever. Root for Slovenia or the Swiss. You have your reasons, and they're yours (and mine are mine, such as they are). Don't make me no nevermind.
Here's a for-instance:
Watching the 2-man bobsled last night (managed to not see the results before watching on network TV), I was glad to see the veteran Russian, who never won a gold medal, win, even though the US team was in medal contention. I suppose under some circumstances, I'd have pulled for the US sled, but that driver had already won a gold medal in his career. I'm still glad he finished on the podium, but it didn't bother me in the least that he finished behind a deserving champion from another country.
Point: I reserve the right to root for whom I want on a case-by-case basis, with the reasoning being totally of my own choosing, even if it's merely a whim. Sometimes that reasoning is "because this competitor/this team is from the USA." Sometimes it's another reason, like with the ice dancers. Glad they won - that they are a US team is, I guess, a bonus for my patriotism.