The problem with gender essentialism is that it means that only half of humanity can be saved because only half of humanity was assumed by Jesus. Jesus Christ is a man. Thus he assumed male nature and women have yet to be redeemed. They must await the coming of their Christa.
Slavery's depravity is so obvious to us today that it obscures the collective mental conversion required to achieve this bit of moral clarity. And religion is often cast an impediment to slavery's stigmatization.