Strange, I thought slavery was practiced in west Africa as well, you know by the non-christian Africans who went and enslaved other non-christian Africans to sell to the Europeans and Muslims or for their own use. I guess Christianity arrived before the Europeans, weird...

Also the Atlantic slave trade would have occurred one way or another, the fact that they where converting the slaves to Christianity is actually something you would expect any half-decent christian to do. I mean if you know someone is going to hell forever wouldn't you try to at least stop it? You could try and say that they didn't really believe in any of it but I really don't see any evidence showing this.