I'm pretty sure this is a non-issue, at least at home. Doesn't the band play the National Anthem before the teams come out?
As for the protests in general, I understand the anger that the players feel. It feels to them like racist cops are out there constantly getting away with murdering black people (among other things) and getting away with it due to a racist criminal justice system. It also feels to them like black people get the short end of the stick from the criminal justice system in general. Cases like the ridiculous sentence that the white Stanford swimmer got show that they certainly have evidence to back up their feelings. I'm sure if he was a black football player, he would have received a MUCH harsher sentence.
I just think that protesting the anthem/flag is protesting against the wrong thing. The country (which the flag and anthem represent) does not stand for racism and oppression. Long ago it did but thankfully it evolved and doesn't anymore.
Of course there are still racist people (some of whom are cops) in the country. They are a very low percentage of people. The problem with the type of protest they are doing is lumping the majority of people into the category of racists. That makes non-racist white people get defensive when they see the kneeling. In turn, that leads to dividing people to have arguments along racial lines instead of uniting people to confront the issue at hand.
Players could easily call attention to the issue by wearing T-shirts during post game interviews or even putting some kind of sticker with a symbol on their helmet in violation of NFL rules. Dare the NFL to fine them for trying to highlight an issue. Hell, if they went about it the right way, they could probably get the NFL involved and get approval for players that want to highlight the issue to be allowed to put a sticker on their helmet or patch on their uniform.
If some white player was a KKK member and kneeled during the anthem to protest that blacks were allowed to vote, I doubt very many "free speech advocates" would be defending his right to protest. Granted, he'd get his ass beat in the locker room but I'm trying to make a point with a hypothetical. Just because you have the right to do something, doesn't mean it is appropriate to do or the best course of action.