The Anthem thing is a fair question, but it is played. It is to be respected. If it wasn't, then it wouldn't be an issue. But it is.
As to the rapist/murders, I think it is accumulative. I have been growing disinterested more and more every year. In large part because there are a lot of bad dudes in that league, and I don't mean that in a good way. I have been around a number of them over the years, as I know you have. This isn't a secret.
The anthem thing just pushed it over the top, and it wasn't just the players demonstrating, it was also how the league handled it.
Football is entertainment, no different than anything else. Once it stops being entertaining, for any reason, then it stops being what it is supposed to. I have walked out of movies I thought sucked and I can turn off a football game (as long as RU isn't playing, that is emotional, lol) without a second thought.