Because the NFL is a business... the Team is that players job. Go tell your boss $#%% you I am doing what I want. You get fired. If the team voted 100% and you did your own thing than I can see that being an issue for that player.
That's my point Mark. And the team owners have rules as well saying they're to be on the sideline for the National Anthem.
Edited (Upon further review):
Maybe because of my military service and understanding of what the flag represents, I admit to having a hard time enjoying games because of these demonstrations. I don't see this as a right or left issue. Most Americans don’t want their flag disrespected, especially by millionaire, wet-behind-the-ears athletes who are paid to entertain and have no clue what the anthem or flag represents. (I mean really, sit or kneel for our anthem in London but stand for God Save The Queen, the anthem for the country we won our independence from and country who supported the Confederacy?)
Add in a POTUS who is great at over-the-top, provacative, unreasonable and idiotic statements capitalizing on current concerns and fanning flames. Trump has been successful in making this issue even bigger and getting the players and owners to unite against him as being divisive. The same owners who ignored the divisive acts by Kaepernick and his media allies that injected politics into football in the first place, but cracked down other political acts like 9/11 tribute cleats. It's a set up for the perfect battle.
I don’t begrudge athletes their free-speech rights. Paraphrasing a quote, many of you have probably heard a military member or vet say, "I disagree with what you say or do, however, I will fight to the death for your right to say or do it." But please keep in mind that many of us believe disrespecting the national anthem selfishly puts personal agenda and partisanship above a symbol and ideal of nationhood and unity that many have died for. Owners and coaches who either choose to not participate or allow players to kneel shouldn’t be surprised that more fans booed their teams on Sunday than applauded their (ahem) "bravery". Ironically, applauding this behavior makes you complicit in dividing and fueling this patriotic sentiment and are helping Trump exploit it to his own political advantage.
My viewpoint is that political statements or stances don't belong in the stadiums. Players want to be politicians and use their platform to lecture us, the press is complicit in making them moral spokespeople, and Trump wants to exploit the players for his own personal vendetta. Guess who the losers are? Millions of us NFL fans who who want to relax and unite under our own fandom and cheer for our teams on a weekend after a tough week of work.
The solution? I don't know, but you can't make patriotism compulsory. You can make it understood that disrespecting the flag to make your point is inappropriate rather than pretending to identify with the victimhood of those making these statements and placing them on a pedestal for using our flag to address a cause. Shame on those that do. And I am disappointed in our POTUS for dividing further by throwing gas on it.