Black Christian leaders should be thundering this from their pulpits non stop!
This thread and your comment does bring up something a bit afield of the Koran-to-swear-on flap (IMHO a bit overblown).
As Tom Sowell pointed out, over the time of the African slave trade roughly 15 million Africans were kidnapped into bondage and shipped to the New World, with the same number being trekked overland to the Muslim owners. Where are the decendants of the slaves taken by Muslims? Simply put, there are virtually none. In the Arab world black slaves were either worked to death or strictly segregated by sex or castrated.
Not giving too much credit to the motivations of Western slave owners, which ranged from semi-enlightened to the economic self interest of any "livestock" owner, it still befuddles me that any significant minority of Western blacks should incline toward the religion which historically and to this day (see: Darfur) engages in systematic genocide of their race.
Solidarity with white Christians has not statistically been as important to them as solidarity by skin color. This is not racsim. /sarc