Well let's not forget the crusades and conquistadors. From end of Dark Ages through The Enlightment, Christians had mercenary reasons for colonizing and enslaving non christians. Black, yellow or red skin was a convenient way to justify doing this. By attaching the concept of evil to dark skin, they eased the way to usurping the land of and exploiting people in the name of god.

After the church and later government sanctioned exploitation ended, the mind set of white christians was already set and has been passed along to this day.   Government interjections such as Civil Rights, Affirmative Action and Equal Opportunity has flared a negative reaction in many whites. It is going to take generations, lots of good will, good education to purge it.