I think LBJ answered that question to a young Bill Moyers in 1964. At least it can be implied:

"If you can convince the lowest white man that he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him someone to look down on and he'll empty his pockets for you."

Right. And enable the looked-down-on person to raise themselves to equality and the lowest palefaces will react with FURY. This is true here and in the Middle East, where the Jews, formerly the 'common n***ers' of the MENA region, have raised themselves at least to equality. And the formerly 'superior' group of that region is reacting with the same unappeasable fury.