I went to schools for my theological training where marginalization of blacks, though outwardly condemned, was justified at least on a personal level. Several students believed  in and justified their racism by appealing to the bible’s account of the sin of Ham and his son Canaan. They identified Ham with the African Continent and said that blacks were cursed to be slaves somehow and they did not want to break the rules of the curse or something along those lines. In actuality, it was Canaan who preemptively defamed Noah in some way and received a curse. It had nothing to do with black people at all. Another false justification was that God had separated the peoples and it was wrong to intermarry with others of different ethnicity somehow. God clearly approved of Moses marrying a Cushite woman who was black when Aaron and Miriam objected and Miriam was cursed with leprosy temporarily (see Num. 12 cf. Jer. 13.23). It baffles how some justify their racism.