I will disagree with you since other nations and cultures have a strong and well researched history of the their involvement with the slave trade and the bondage and abuse of humans. There is vey much a historical time trail that is easy to locate when researching the subject. I have also watched many movies, tv drama's and read books on the subject of slavery in other cultures and nations besides the US in the world going back in history even before the birth of Christ. One interesting movie I viewed this winter was the subject of how the slave trade was outlawed finally in England. The turning point was an English trade ship at he time that was full of slaves and how the slaves were allowed on purpose to die since the ship Captain now had nowhere to "store" his cargo and that if the  human "cargo" could make it to the slave auctions "alive" the "cargo" could be "salvaged" and the loss of the ship would not be covered fully in their insurance policy. The men were brought to justice.