Admitting that there are “so many, many positive aspects and benefits to religiosity”, the authors of a meta-analysis on the subject have shown a positive correlation between religious affiliation and racism.
Organized religion […], by its very nature, encourages people to accept one fundamental belief system as superior to all others. The required value judgment creates a kind of us-versus-them conflict, in which members of a religious group develop ethnocentric attitudes toward anyone perceived as different. […]
Studies have shown that religious adherents are more likely than agnostics and atheists to rate conservative “life values” as the most important principles underlying their belief systems.
Those specific values — social conformity and respect for tradition — also most closely correlate with racism. In short, people are attracted to organized religion for the same reason some people are inclined toward racist thinking: a belief in the sanctity of established divisions in society.
Of course there are numerous caveats. The most important of which is that the correlation is strongest with religious fundamentalists and is “unclear” with those who are attracted to religion as a spiritual pursuit (as opposed to those who attend church as an obligation).
The researchers also note that the link is particularly strong with highly educated seminary students, that the correlation seems to have been decreasing in recent decades, and that there is no link between “intrinsic religiosity” and racist attitudes (although there is also no link between this “intrinsic religiosity” and racial tolerance).
via Intelligent Life