Final answer:
Fredrick Douglass described the religion of the South as a justifier of barbarity criticizing how slaveholders used Christianity to legitimize slavery's cruelties and maintain their dominance.
Step-by-step explanation:
Fredrick Douglass, a former slave and prominent abolitionist, described the religion of the South as a justifier of barbarity. He argued that religious slave owners were among the worst, using their faith as a cover to commit heinous acts and maintain their authority. Fitzhugh and other southern theorists contended that slavery was both justified and benevolent, but Douglass's perspective reveals the inherent cruelty and hypocrisy in their assertions. The religion practiced by these individuals, far from being a force for good, was instead used as a mechanism to secure the subjugation of African Americans and reinforce the social and economic hierarchy that underpinned slavery in the American South.