On Why Africa Became the Western Hemisphere's Primary Source for Slaves Starting In the 16th Century (Prior to that the Slavic People of East Central Europe Were the Major Target for Europeans, Iranians, and Turks)

 According to Thomas Sowell, it had little to do with bigotry and much more to do with the emergence of nation-states and empires in Eastern Europe which made it much more difficult for raiders and marauders to capture their Slavic (and sometimes non-Slavic) victims. Africa, being a far more primitive region replete with people all-too willing to sell off their brethren, quickly become one of the few remaining viable options for slavers of all stripes (white Europeans, Africans, and Muslims predominately) and so they took full advantage of it. And how.