The NFL can get away with its insulting behavior because it is an absolute monopoly. Even near monopolies like credit card, package delivery, and cable companies, and airlines do not insult their customers, because there is at least a little choice. In the real world of vicious competition, like retail, no one can afford to lose customers. An insulted customer will go to a competitor instantly, and then tell their friends why.
The NFL is a monopoly in the pro football world. But what if the customer base decides that they don’t care about the NFL anymore? What if they decide to do other things on football Sundays in the fall? What if they decide not to spend so much money on expensive tickets and NFL Sunday ticket, etc?