You have a profound misunderstanding of the trans Saharan slave trade. Over centuries it resulted in millions of West African slaves being transported into and through the Arab world. This may not even have been the most significant source of slaves out of Africa during the pre-European colonial period. It is highly likely that more slaves came from Central and East Africa via Zanzibar. Millions upon millions of slaves being extracted from Africa before the Portuguese arrived. I’m not saying that what Europe did was even remotely reasonable. Just understand that we didn’t invent slavery, we didn’t start up slavery in Africa out of nowhere. It doesn’t excuse us. But we’re not uniquely evil either.