Pete Rozelle would not have put up with it. (Anyone remember what he did to Walter Payton and Jim McMahon for wearing "unauthorized" gear...namely headbands??)
Anywho, Kapernick was the perfect storm. His antics would not have been tolerated in Pittsburgh, or Chicago, or Green Bay, or Dallas to name a few. Only in San Francisco would he and his "Protest" be allowed to happen. And like a cancer it has spread. And the NFL ("Not For Long), doesn't get it. They don't understand that their fan base isn't the guys in the skyboxes, but the guys that watch at home every Sunday, wearing NFL licensed jerseys with hundreds if not thousands of dollars in other NFL licensed merchandise. Lots of both Blue and White collar guys who can maybe afford a ticket or two every year to go see a game. But guys who love their country, imperfect as it may be.
They already get enough politics and diverseness, in the news, in the movies, and even at work. Come the weekend, they want to put put on the jersey of their favorite team, get together with their buds, drink some beers, and chow down while watching the game. Then comes along this multi-millionaire who says that the country they know and love is "bad". They just want to be entertained for a couple hours and leave all the politics and bushwa behind.
So, just like Hollyweird's box office receipts have tanked since they've gone full Trump Acceptance Rejection Derangement Syndrome (TARDS), so too has the NFL's. Viewership was down 11% last year. It's down a further 14% this year. Seats, in not just San Fran/Santa Clara and LA are going unsold, but in other cities as well. Even on the Secondary Markets. Especially in those cities that have allowed players to kneel.
The NFL thought it was above the fray and nothing could topple their empire... Well, it looks like there was a Trojan Horse. And like a cancer, once it wasn't stopped and allowed to spread, it's all over for the NFL. They continue to alienate their fan base and it's too late to do anything to prevent it.