What people forget is that slavery was not created by America, or even by Europeans. Slavery was an ancient practice. Everyone from African tribes to the Chinese to the Greeks and Romans to the Native Americans practiced it in some form or another.
Arabs used to charge 7 times as much for eunuchs as for other young slaves - because that was the death rate when they cut off a boy's "equipment" to make him a eunuch. Only 1 in 7 survived. The African tribes who kept slaves were happy to make money selling them to the Arabs and to Europeans.The Romans made some slaves fight to the death in amphitheaters for entertainment.
The first people to totally outlaw it were the British, I think. We Americans fought a Civil War to make it illegal in our territories. Nowadays, no civilized nation allows it LEGALLY but it still continues in the shadows... and it must be totally eradicated. It is an ancient evil.