A lot of bitter frightened old white people upset because there's a black dude in the White House.
And as they have so often in the past, the plutocracy exploits these fears seeing an opportunity for a coup d'etat. They know from past experience that nothing breaks a union like a busload of black or brown scab workers during a strike. After the race riot is over, there's no more union, and people are left more desperate than before, and willing to work for even lower wages. What worked in West Virginia coal towns, they now reason, might work on a national scale.