NFL owners are not trying to preserve honor and respect for the American flag. They are trying to make the NFL a safe space with limited speech, and protect a legion of easily upset fans so they don't throw a tantrum and change the channel because something made them mad.
The League has every right to do this. In this great country, you have the absolute right to prioritize profit over morality. You can suppress protests, then sell patriotism to stuff your pockets with cash as much as you want. It's a free country.
And if you can do so while accepting public funds for stadiums, so much the better. Hooray for private enterprise!
But now the NFL is akin to ultra-thin-skinned universities where safe spaces protect people from thoughts and opinions they are offended by. The snowflakes on the right are just as delicate and sensitive as those on the left. They need rules and regulations to protect them from the realities of the world.
Anyone embracing this rule is as dainty and weak as a college student offended by the movie How the Grinch Stole Christmas.