the British were big participants in the Atlantic Slave Trade, the movement to abolish Slavery began in Britain long before it began in the American colonies. When Lincoln signed the Emancipation Proclamation, the South lost all hopes of the British intervening on their side.
Racists have even tried to use their religion to justify their superiority. Just like with everythingelse to justify their intolerance. That is why some people even dare to question religion itself. People have been conditioned to believe they are superior to others. They will end up the same like every human. I read a story of a Jew in Poland, that fled across the river, to escape the Nazi invasion because they deemed her inferior. All her relatives were not as fortunate and did not escape. She sought refuge among others who hid her when the Nazis pushed further.
Today that Jew is very old and still lives in Poland. There are very few of them left because many of the younger generation left the country and went to places like America or Israel. That Jew remained in Poland and knows what it is like to be oppressed by another race calling themselves superior. She remains in Poland because she does not use her oppression, to act like those who once oppressed her. She knows all too well that she is not superior to anyone, when she looks at the grave stones of what was once a proud people in Poland.