Our culture is 100 times different, anyone who watches a UFC or PRIDE event can tell the difference in the respect fans have for the sport. As you pointed out, it's the same in baseball. I used to live in Baltimore, the entire house yells "ORIOLES" or some shit during one part our own national anthem. Stupid example, but you get my point. American fans, half of which at sporting events are drunk as shit simply don't care about respecting other countries. We go from being patriotic to plain out pro-America and anti-anyone else. It's just the way it is, of course I think it's stupid but with our freedom of speech and the way our culture and society is, it's no surprise when fans do dumb shit like that. It's never gonna change, not in our lifetimes.
Basically, case in point even though it's something I just said above:
We go from being patriotic to plain out pro-America and anti-anyone else