They want to conduct business as a non-profit? So be it.
No, seriesly. Look it up. The NFL conducts business under non-profit status.
Tell you what. I'll save you the trouble. You don't have to look it up. I'll provide the link to the video for you....
SAY WHAT?? That's as outrageous as governments providing funds and tax breaks for stadium construction. Would you believe this year Cleveland's councilors action went along with a request from the Browns for a few million dollars to help fund improvements to the stadium, including a more excellent scoreboard?
The NFL is in self destruct mode, and they don't even know it.
The NFL is a non-profit because it is operated as a expense for the teams. It costs money to have league offices, officials, marketing, etc. Any money for TV contracts or merchandise licenses is sent to the teams. Thus the NFL Incorporated makes no profit. This is the opposite of most franchisers like McDonald's where both the parent company and the franchisees make profits.
Imagine if the airlines formed a trade association to come up with standards for airports, runways and combined scheduling (and they might have such a trade association). The airlines would be the corporations which made the money, while the trade association wouldn't make a profit. If it did, it would be expected to reduce fees to the member airlines.