If a bunch of students want to look like politically correct idiots, and being used as pawns for politically correct causes, then let them make their own choices, as long as they are within the laws of the land and the du Lac policies.
That being said, it's common courtesy to stand for the National Anthem, and pay your respects for those who have died for this country, and not to use it for your own politically correct platform.
Protest on your own time, at a different event. Don't screw up the atmosphere for the tens of thousands of fans who paid good money to see that game.