This is nothing but an opportunistic business move by Cuban. He's made anti-NFL comments before, and this is just an opportunity to pounce.
This same guy rode hard for Sterling....and make no mistake, this is no safe haven league for black men. It's still owned by billionaire cacs who see the players as property.
I think the backlash would be slightly less if Kaep did this in the NBA. Simply because middle American cacs make up less of the audience, and blacks make up more of it.
Both league still try to grandstand with this pro-military "thank you for your service, now let's kiss the ass of a random soldier to make it look like we care". It's all to appease Joe middle America.