Also, this report is definitely a lot more than a little bit whitewashed.

Tribal warfare was a constant given, and rather than slaughter captives in the customary manner, the victors learned to profit by selling them to the Arabs, who in turn sold some of them to the Europeans. Eventually, some tribes took to supplementing regular warfare with slave raids on their neighbors, capturing and hauling off men, women and children for sale.

And, that Africans treated their slaves so nicely, if you believe that, I have some time-shares I'd like to sell you. You can be sure the Arabs they sold most of them to were not gentle with them. African chiefs were not known for nicety either.