I was at Game 3 of the 2015 World Series.
I have watched thousands of renditions of the Star Spangled Banner before baseball games throughout my lifetime. Now I usually take my hat off during the Star Spangled Banner, for reasons I still don't 100% understand other than "respect" (I mean, who really cares, it's just a piece of cloth over a person's head), but this time, I forgot to take off my hat.
Count my lucky stars to have encountered a fellow Mets fan (who was probably already drunk) to let me know I had my hat on. From behind me, he grabbed my hat and hurled my hat across the floor. "Take your hat off!" he said. I was totally stunned and mortified. The reactions were mixed. My dad pushed and jawed at the guy. Another parent with children with him yelled back. Other men (who also probably never been laid before, sorry, had to throw that in) sided with the drunkard because throwing another person's cap to the ground for any reason is justifiable. I shouldn't be forced to take my hat off (I do anyway to avoid conflict). Honestly, I'd prefer leaving my hat on my head so that I have a free hand to hold my nachos.
When it comes to the NFL and kneeling during the National Anthem, the reasoning should be the same. If their kneeling isn't getting in the way of anything you're doing, leave them alone. Take your anger out on the guy who made your nachos for skimping on the cheese sauce, or the long line at the hot dog stand.
Now, I don't quite understand the reasoning behind kneeling or the change that players expect to occur because of kneeling. Maybe their 3 years late to the Tim Tebow party? Anyways, that's a story for another day.