Really wish this accusation would stop being repeated over and over, its quite misleading.
The NFL is a 501(c)6 organization, same as a chamber of commerce, boards of trade which are not organized for profit and no part of the net earnings goes to the benefit of any private shareholder or individual. Basically it organizes a whole bunch of associated businesses. The non-taxable part is only for the organizational aspects. While its true that the money does filter through the NFL - the overwhelming majority ends up in the hands of football clubs who operate and are taxed like any other business. Beyond that, the tax revenue from ticket sales, hotels, income, corporate and entertainment taxes makes having the NFL in your city a massive tax boon.
That said, the NFL wields a huge (almost concerning) amount of economic power -- they are using their prime position to bully themselves into better economic agreements, which is pretty much what I would expect of a well run business. Nobody forces anybody into doing business with them, its just that the benefits generally far outweigh the costs.
The exposure for a Super Bowl half time act is huge, the beneficiary in the long run is the act, not the NFL. So, an act paying to play sounds crazy, I'm not so sure it is. Especially when busineses happily line up with millions of dollars begging to get airtime for Super Bowl ads. I'd contend most viewers are more interested in the ads than the half time show -- the NFL would get less negative attention if they just replaced the half time show with more commercials, problem solved.
.dew.