I am not even talking about the slavers. Entire villages would be displaced, fleeing because slavers were in the area. As slaving expanded, a kind of no-man's-land developed as people tried to go into hiding.

And between slaving raids, those who were able to keep hidden could barely carry on economic activity due to the threat of raids.

There was also slavery within Africa and descendents of those slaves still live in Africa. First the ivory then the rubber industry were founded and sustained on slavery within Africa.

The fact that many Africans participated in slaving, though Arabs ususally ran it at the top tiers, does add a whole layer of complication to the issue. But there were many victims of slavery in Africa either because they lost a loved one or many loved ones, or because their village structure got destroyed because of slave raids, or because they were enslaved within Africa.