Of course there are people of faith who are part of mixed-race communities, and who have been active in the civil rights movement. But they are the minority overall, and for the majority the sense of in-group vs out-group, moral vs. immoral, them vs. us, appears to be tracked by racial identity too.
From their abstract:
Religious racism partly reflects intergroup dynamics. That is, a strong religious in-group identity was associated with derogation of racial out-groups. Other races might be treated as out-groups because religion is practiced largely within race, because training in a religious in-group identity promotes general ethnocentrism, and because different others appear to be in competition for resources....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.I'm going to speculate that this sort of correlation is true for any sort of group identity, whether it's a social club or a neighborhood association or a church: us vs them. But, there aren't many group identities remaining in our restless, mobile culture, and even church identity is declining.
Their abstract also says,
In addition, religious racism is tied to basic life values of social conformity and respect for tradition. In support, individuals who were religious for reasons of conformity and tradition expressed racism that declined in recent years with the decreased societal acceptance of overt racial discrimination.Now, given that kind of observation, it's not surprising that anti-GLBT sentiment is also stronger in church groups--and it's still very socially acceptable to be anti-gay. Again, yes, we know that is not true of all church groups, but as we learned in the Prop 8 trial, numbers count-- and you can't count the UCC as equal to the Roman Catholics because there are many more RCs.
So, how do you break down the "us vs them" while keeping the good part?
Why Don’t We Practice What We Preach? A Meta-Analytic Review of Religious Racism Personality and Social Psychology Review, Vol. 14, No. 1, 126-139 (2010)