[SmokingJoe]

They don't need to apologize for sh*t.
Are you aware that every single civilization in history, including in Africa before the White man ever stepped there, practiced slavery?

[Cronos]

“every single” — true, when mankind transitioned to an agricultural/animal husbandry system, then slaves became needed and especially so in cities (i.e. “civis” - so civilization). There is one exception to that rule - the Indus valley civilization - with large cities but no instance of slaves. It is puzzling