Indeed lost in the kneeling controversy is Trump's expressed frustration with the NFL's concerns (such that there are) about head injuries.
"Today if you hit too hard — 15 yards!” Trump said at a rally in Alabama. “They’re ruining the game.”
Apparently he is against the players kneeling but it is okay, even preferable, if they stagger around a bit after repeated concussions and eventually progress to dementia. As long as the don't fall to their knees I guess.
Really- it is a small price for the players to pay for the privilege of entertaining him. And the essential core of the entertainment for Trump is watching the violent hits; strategy, skill, scoring just aren't enough to hold his interest.