Alternative thesis:  Maybe, rather than most of Americans being white supremacists, they simply did not like Hillary.  

White supremacists used to be a term used for skin head Nazis, Aryan Nation, and the Klan - the kind of people who carried torches at Charlottesville - the fringe of the most racist people in America.  The idea that Trump and most of those who voted for him are all white supremacists is either ridiculous or a complete redefinition of the term.

The NFL is not a conspiracy to kill black men.   Black men dominate its ranks because they have the skills and abilities to play the game well.  And they are most dominant in the most athletic positions - cornerback, wide receiver, and running back.  They also dominate basketball and track and field for the same reasons, but nobody is suggesting that this is some sort of conspiracy.  The NFL could be doing more to make the game safer for players, but the foot dragging has much more to do with money than with race.