the crowd was protesting the "suspicious" absence of their star (who reportedly had issues with passing the drug test). Relax, it is nothing against the Americans. It is not always all about USA, you know?
BTW, what do the actions of a bunch of sports fanatics have to do with weather you like an anthem or not?
My personal favorites are the Scottish (both of them are great, just like both flags are gorgeous), old Soviet (witht eh lyrics and all) and the Israeli.