The NIKE / Colin Kaepernick ad read, 'Believe in something. Even if it means sacrificing everything.' The soldier in the coffin who gave his life so we could be free is the one who has SACRIFICED EVERYTHING. We of course have the right to protest but Kaepernick may as well be knealing on his flag. NIKE doesn't get my money. 
William G Walsh  is an example of a real selfless hero. 
https://www.nationalww2museum.org/war/articles/sergeant-william-g-walsh-medal-of-honor