The nfl, nba (and other sports organizations) are also non profit and exempt from paying taxes. Stern made 70 million last year as commissioner of the nba...
I've thought about this and the problem with charities is that there just aren't enough of them out there to help all the people that need it. Even the governmental programs can't help everyone that needs it so the two have to co-exist so that as many people as possible can get the help that they need.
“Fairy tales are more than true; not because they tell us that dragons exist, but because they tell us that dragons can be beaten.”
― G.K. Chesterton