Well depending on how you look it you cant really say "white". Slavery has been going on since 3000BC with the Egyptians. It then progressed through the world and through time until it was seen as very common place. It was even wrote in the bible as being a ok thing. And it was even made more "mainstream/known" with the Arab Slave trade which had 3 times the amount as the north american slave trade. So thats why they thought it was a ok thing