They are EMPLOYEES. It is NOT their public forum. These imbeciles are nothing more than hired hands. If they cannot represent their employers in a favorable light they'll be canned for being the useless scum they are. Let them take their fking knee at home.They don't just get paid for game time. If a player never plays in a game, he still gets paid. NFL players have to attend practice, team meetings, workout sessions, ect. When they are in uniform and on the field on game-day, they are representing their team and employer.
I think it is ultimately up to the team owner, if he wants to allow it, then I think it is OK. He will lose a lot of revenue because of it, but it is within his rights to allow it.
Otherwise, employees typically don't have a "right" to engage in protests while "on the job". Do you see Best Buy employees protesting while at work? Do you see police officers or government employees protesting while at work? No.
Except Best Buy workers aren't given a public forum. NFL Players are.
Don't whine because you've given these guys a public forum and they say something you don't like.