I've always been of the impression (on the very rare occasions when the subject crossed my mind) that they were subsidized because they football is uniquely American, because it's virtually a symbol of America itself.
Even the NFL's most committed apologists are going to have a hard time explaining how a sport that's a "symbol of America" can also be a sport that makes a public show of dishonoring our flag and our National Anthem.
I expect them to try it though. I expect them to double down on that end too.
Another article on NFL corporate welfare:
Taxpayers put up $1.3 BILLION for the new Atlanta stadium.
Don’t give them the handout? The owners threaten to move the team.
But the NFL has been trying to expand globally for a long time, so they have to play down the “Americanism” aspect. That’s what a lot of this crap stems from.