One other thing, contrast the NFL with how NASCAR treats the National Anthem. I don’t even like NASCAR but I know they and their people respect all the great gifts this country has given them and it shows.
Even though NASCAR supports the National Anthem, they are dying on their feet. They killed the product.
The NFL has the same problem but doesn’t realize it yet. With the commercials, the games have become unwatchable. In person, with all the commercial time outs, they have become boring.
The appearance of political correctness and social justice is going to make fans realize the NFL just isn’t a watchable product any more.
NASCAR also has a prayer (invocation) before the race, and a military fly-over, as well. They’re doing it right, so far.
The NFL has a lot of authority to micromanage details of the game on the field, but the teams still operate as their own companies and are subject to the rules of the league-wide collective bargaining agreement with the NFLPA.
I don't think the NFL deserves a lot of criticism for what it is doing on a league-wide basis here. The NFL simply doesn't have a lot of options right now. Individual team owners, on the other hand, can set the rules for the conduct of their own players, and some of them have done that.
The NFL really can't do very much here until the CBA expires and any requirements for the national anthem are written into it. This is exactly what happened when the NBA faced the same problem back in the 1990s.