We pay handsomely to watch these players perform, many of whom are privileged, highly paid, spoiled young men, making more than fifty times what the average fan earns.
We don't need them lecturing us on politics or any other non-sports subject.
They should play the game and entertain us and when they are done, if they have an opinion they want to share, have them do it sans the uniform, on their own time outside the stadium. The American flag was and always will be a symbol of freedom fought for and died for, by hundreds of thousands of our military heroes over 231 years.
Let them stand and place their hands across their hearts and pay respect for a couple of minutes in recognition of the freedom others died fighting for, so they can live in a free world and play a game for which they are paid millions of $$$.