(First I will note that Christianity was by itself the first way of discriminating or segregating in American society...)
Christianity: FORCED on Africans and the FORCE of RACISM
- Segregation itself was a continuation of slavery, both being the product of racism, which in turn was a product of Christianity.
It was a fundamental Christian belief, expressed in the Scriptures and repeated by later Christians, that all pagans serve Satan and that Christians had a right to protect themselves against corruption by pagans and a duty to save the pagans if possible from eternal damnation and torture. These beliefs led them to slaughter or enslave millions of European pagans in centuries of crusades, until all of Europe was Christianized.
We know this today because Christian clergymen proudly wrote lengthy chronicles describing in nauseating detail the atrocities Christians committed in forcing pagan conversions.
When 15th-century Christians discovered new lands full of pagans, they did to Africans and American Indians exactly what they did to European pagans, only with one difference. For centuries, Christian artwork had depicted Satan and his demons as black. In Christian literature, Satan was described as black, even specifically as an African, such as in Athanasius' Life of Saint Anthony and the medieval best-seller Voyage of Brendan. Not surprisingly, Christians decided that Africans and Indians were a lot closer to Satan than white-skinned Europeans and acted accordingly to protect themselves from the "pollution" of contact with dark-skinned peoples. Read historian Forrest G. Wood's The Arrogance of Faith for an in-depth exploration of the Christian origin of racism, slavery and segregation.
That's why defenders of slavery in the antebellum South repeatedly use the Bible and refer to Christian concepts in their arguments. Read The Ideology of Slavery, which reprints slavery defenses, edited by Drew Gilpin Faust, to see how devoutly Christian the defenders were. Defenders correctly note that the Bible repeatedly condones slavery, even commands it at times, and never condemns it. Even the Tenth Commandment condones slavery; so much for the Commandments as a source of moral virtue. Also read Proslavery, by Larry E. Tise, pages 116-120, for surveys showing the overwhelmingly Christian character of slavery defenses. In one survey of pro-slavery tracts, clergymen wrote more than half.
In the aftermath of the Civil War, it's no surprise that Sunday morning became the most segregated time of the week. Nor is it surprising that it was agnostics and atheists in various liberal movements who spoke out first against segregation and racism. That's one reason that white segregationists--clergy included--labeled the civil-rights workers "communists," a word they considered synonymous with atheism.