You’re making several mistake here. Owners often regarded slaves as people. They just didn’t regard them as free. And people learn to do better — that’s why it’s significant that Franklin freed his slaves and became president of an abolition society. Can you name any black slave owners who did something comparable? I assume there were some, but I don’t know of any — the famous black abolitionists were slaves, not slave owners. Most black slave owners, like most white slave owners, kept their slaves. Out of curiosity, do you think black slave owners also didn’t think their slaves were human?