Kenneth Stampp in his book, The Peculiar Institution: Slavery in the Ante-Bellum South, suggests that some owners of slaves were conflicted about the need to apply punishment in the control of slaves and yet most felt fully justified in imposing that control. He sites on numerous occasions the willingness of owners to overlook the cruelty of overseers if they met or exceeded production goals. This head-in-the-sand approach to ethics undoubtedly had many causes but the most obvious was greed.
Owners also considered their slaves to have a “duty” to their master by virtue of the fact that they were, after all, his property and that the master provided and cared for them. But the most prevalent justification for imposing control on the slaves was to achieve maximum production from them as a labor force. Poor performers, for whatever reason, were seen as impacting the bottom-line.