The problem with this entire topic is that it's getting muddied by the "patriotism" argument, which the left actually loves because it makes their unreasonable position look more reasonable.

So when the narrative goes like this:

Right: It's unpatriotic to kneel during the anthem, and this shouldn't be allowed! Good for the NFL!

Left: Actually, political protest is very patriotic, and has taken place since the beginning of this country.
... then the left appears to be winning the debate, and the right looks like a bunch of flag-waving rubes.


But frame it the way it should really be framed:

Right: These players are very highly paid employees of NFL teams, and their on-field political protests are upsetting the majority of fans and harming the NFL's brand. The NFL has every right to demand they stop this behavior while at work. Furthermore, the NFL is allowing any player who doesn't want to participate to opt out and stay in the locker room.

Left: No!! Black people are oppressed! They need a voice! They need TV time! Protest should be allowed anywhere, any time, for any reason, and no one should ever be able to stop it!
... then the left looks like a bunch of loons.

Still boggles my mind that people believe an employer shouldn't have the right to force employees to cease controversial conduct at work which angers their customer base.

Like, that's the most basic of basic concepts in the employer/employee relationship.