The NFL is dumb if they rally behind leftist ideology. A lot of "liberal" opinion leaders want to see football go away or at least be modified to the point it's unwatchable, thereby eliminating the appeal from high school and on up. Less people watching means smaller paychecks. People on the right tend to favor parents making their own choice as what's ok for their children to participate in and will fight to keep football as it is i.e. entertaining.
Down the line, football players are really shooting themselves in the foot by alienating patriotic Americans, who mostly tend to be from the right. But keep siding with leftists and giving the finger to people on the right and watch what will inevitably happen.