There was never any reason to link sporting events and nationalism. We don't play a national anthem before every concert. Or before every movie. That would be ridiculous--the only reason most people don't currently see an anthem before every game to be ridiculous is because they're used to it.
Sports are entertainment. They are not intrinsically "salutes to our troops" (as it's often turned into, with excessive gestures like fighter jet or stealth bomber flyovers). If we want to appreciate our troops, we should treat them better in terms of the social services we offer them when they complete their service. Not ultimately meaningless shows of jingoism at sporting events.