The collective bargaining agreement between the NFL and the players limits the owners in terms of how they can punish the players over this nonsense, but there is nothing that prevents a team from benching a protesting player and then cutting him at the end of the season. We have now had two seasons end since this "protest" first started, so any player who is still "protesting" is clearly doing this with the approval of his management.
I agree the owners are a big problem.