Here comes the science...

From TFA:

The February issue of Personality and Social Psychology Review has published a meta-analysis of 55 independent studies conducted in the United States which considers surveys of over 20,000 mostly Christian participants. Religious congregations generally express more prejudiced views towards other races. Furthermore, the more devout the community, the greater the racism.

We also read this additional fascinating conclusion from the authors' summary:

"The authors failed to find that racial tolerance arises from humanitarian values, consistent with the idea that religious humanitarianism is largely expressed to in-group members. Only religious agnostics were racially tolerant."