Follow the money guys. The DoD has been sponsoring professional sporting events for over a decade. Most recently thanks to PATRIOTS like Sen. John McCain, this spending of US tax dollars has virtually stopped.
The irony is that prior to 2009 do you even remember player being on the sidelines of football fields? No because players were in the locker rooms for pregame festivities like the singing of the anthem
So here is the irony. For 78 years (1931-2009) there was no players on the sidelines for the anthem. The decision was made by the NFL to take millions of dollars from the DoD to promote patriotism (Propaganda) In less than six year, Colin Kaepernick was able to turn that blood money move into the biggest marketing mistake of the NFL since the strike and the scabs (remember that season)
Just a different prospective to consider.