"In 1452, Pope Nicholas V issued the papal bull Dum Diversas, granting the kings of Spain and Portugal the right to reduce any "Saracens (Muslims), pagans and any other unbelievers" to perpetual slavery, legitimizing the slave trade as a result of war.[119] The approval of slavery under these conditions was reaffirmed and extended in his Romanus Pontifex bull of 1455."
Slavery is a vile practice, but the constant drumming implying that it was essentially a white on black phenomenon is utterly fallacious.
In fact, slavery still exists to this day in many NON WHITE countries. (see above link).