I've never seen such socialist, anti-American drivel with the exception, I guess, of the flag burning radicals in the 1960's. But its much more widespread and institutionalized now days. Back then almost any member of the NFL, more than likely, would have kicked another  team members rear-end for doing something so disrespectful. They would have been ashamed of that member and  not praising him to the  high hills.  Just another 'sign' of the times and how far we've 'fallen'. And we're still falling...  
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Yes, they have the right to disrespect our flag and stomp on everything it stands for. NFL football 'players' have that right unlike at Berkeley, where free speech is only for those who have  similar leftist viewpoints.  If the rest of America decided to 'act' with the same  manner of 'tolerance' as some  students at  Berkeley do, those football players would be in jail right now. They really would.