I agree. I love John Cleese and all the Pythons, but he is making an important category error here: slavery in the ancient world was commonplace, and was, in effect, the more humane alternative in dealing with the perennial POW problem after a battle (at a time when warfare between city states and their allies were endemic, as in Greece, and imperial warfare to gain new lands was the very foundation of Rome and other ancient empires.) The less humane (and less profitable) alternative to the POW problem was, of course, massacre.

Fast forward to the 17th to 19th Centuries, and slavery became something altogether different: a transatlantic commodity to provide a much-needed labor force for sugar, rice, tobacco, and cotton plantations in the Caribbean and the American south. And THIS slavery, unlike the ancient version, was racially coded and intergenerational. Whereas ancient slaves could (and often did) purchase their freedom and become citizens, that option was foreclosed to African slaves based on "race" or ethnicity alone. This was an intergenerational crime against humanity far worse than the ancient world's exploitation of their POWs.