While this may be technically true, he wouldn't be seen as Korean by the vast majority of Koreans, regardless what he considered himself. A Korean born in another country with another nationality would be considered more Korean than the white guy. I don't mean that as a knock against Koreans. Korean society is a lot more homogeneous than in America or other diverse countries.
I can kind of understand that, but I guess I also feel it's kind of unfortunate. If I was born there, and considered it home, and considered it my culture, and considered my fellow Koreans my countrymen, then I would be disappointed that those feelings weren't reciprocated just because I looked different and my ancestors were from somewhere else.
After all, what would I know of France? Some stories my parents told me?
As for other ethnic groups, I can't say. But if you've ever seen, for example, a soccer game between the US and Mexico, there are often more Mexican flags on display than US flags, even when the game is being played in the states.
Also unfortunate, I think. Honestly, I feel like if you consider yourself Mexican first and American second, then go live in Mexico.
I respect all the athletes in the Olympics greatly, and in some sense cheer for all their successes, but of course I cheer loudest for the US, regardless of the race or ethnic background of the athletes who fly the flag. Even if they weren't even born in the US but came from somewhere else and have become citizens and call America their home now, I consider them as American as anyone else.
I guess, to me, that's what's beautiful about this country. If you love America or what it stands for (despite the fact that it's obviously not a perfect country), and want to be an American, then you can be. It's a melting pot made up of all kinds of different ingredients.
Just look at Arnold Schwarzenegger. Who's more American than him?