Why do Centro Americans root for U.S. when they play against Mexico?

I don't get it. They go for U.S. and blame Mexico for all their problems when the U.S. is the one who started most (if not all) their problems. Gang problems, anarchy, racism, poverty, social inequality, quality of soccer, immigration issues (U.S. pressued PANmierda to be more strict in Chiapas). Y yo el pendejo que quiero que quede El Salvador, Honduras, y Costa Rica en el mundial y no Estados Unidos. Bueno, I still would want those teams in the World Cup rather than the U.S. even if they hate Mexico.