Like "white slavery," as if non-white slavery were a standard with few exceptions, instead of just one piece of the general pattern of enslavement covering every period of history and every population group.
I am currently listening to his book “Conquests and Cultures”, and he goes into great detail on that very subject. Funny how the most prolific slave merchants (over the longest period of time) have been Muslims, and how muslim countries were the last ones to ban it (and even still engage in it despite banning it for PR purposes)
They don’t have those facts in today’s textbooks in schools.