They did not know

Again, the terms “civilized” and “Christian” begin to have a very strange ring, particularly in the ears of those who have been judged to be neither civilized nor Christian, when a Christian nation surrenders to a foul and violent orgy, as Germany did during the Third Reich…. From my own point of view, the fact of the Third Reich alone makes obsolete forever any question of Christian superiority, except in technological terms. White people were, and are, astounded by the holocaust in Germany. They did not know that they could act that way. But I very much doubt whether black people were astounded—at least, in the same way.

James Baldwin
The Fire Next Time (1962)