Most of the slaves they got from Africa were purchased from local slavers.
Hahaha oh jeez, that's some bull shit propaganda and false. No, most weren't sold by local slavers. At best, you might have a tribe that sold another tribe that they had taken as slaves following a war, and the basic idea was if they didn't give the Europeans slaves, they would be enslaved themselves. Of course, as the slave traders from Europe had zero honor, they'd end up reneging on that "deal" so. Maybe don't suckle the teat of that pro-southern white nationalist propaganda.
So are you under the impression Europeans got most of their slaves by regularly traveling deep into Africa and rounding them up by the millions with nets on horseback?
You're adding in the horseback details, but yeah, they traveled deep in to get the slaves. Do you believe that is any more believable than your suggestion that over the course of 300 years, "local slavers" were able to sell 12+ million slaves from the African interior? Can you name any of these alleged "local slavers" or the nations/ tribes from which they hailed?
Compare a map of Africa from 1700 to 1900 and this will debunk your post easily. What they never teach you in school is that Africa actually had functioning kingdoms and wasnt just cavemen living in some jungle. It took modern technology and developed nation states for a European power to pull of a Battle of Omdurman let alone the Europeans still got a couple of nose bleeds fighting with modern technology as opposed to crossbows and swords against the Aztecs.
Still waiting on proof of local slavers, got any tribe names or leaders?