Even still, there was slavery throughout the Americas before European contact. Korea, China and Japan had rotating power dynamics with slavery involved. India's caste system has slaves on the bottom and is a several thousand year old system. The Arab world has been full of slavery going back to biblical times and continuing to today. Africa had slavery throughout.

Even the slavery the west promulgated in the last 5k years has often been a multi-party, multi-ethnic practice. The transatlantic trade was Africans and Arabs kidnapping and trading Africans and selling them to Europeans. And during the same time period, there was a large Arabic trade in European slaves.

It's never been one culture that was responsible for most or all slavery and it is objectively true that Christians in the west spearheaded the end of chattel slavery.