This is an excellent question, and one you should probably be asking of yourself. The fact is, treatment of slaves in the antebellum south was brutal and degrading in a wide variety of ways. It was especially bad for female slaves, who were frequently subject to sexual violence, not to mention forced separation from their children. Lie to yourself all you want, but the fact remains, slaves were routinely subject to either actual beatings, or the threat thereof, extraordinarily long workdays, unsanitary living conditions and the diseases and high death rates that accompany same, and of course an almost total lack of legal rights. For example:
"Yet we must never forget that these same welfare capitalist plantations in the Deep South were essentially ruled by terror. Even the most kindly and humane masters knew that only the threat of violence could force gangs of field hands to work from dawn to dusk, "with the discipline," as one contemporary observer put it, "of a regular trained army." Frequent public floggings reminded every slave of the penalty for inefficient labor, disorderly conduct, or refusal to accept the authority of a superior." - David Brion Davis (an historian at Yale and Cornell).
And this:
"Buried in tattered and filthy blankets ... here, in their hour of sickness, lay those whose health and strength are spent in unrequited labor for us ... to buy for us all the luxuries which health can revel in." - Frances Anne Kemble (a prominent abolishonist, married to a plantation owner) -http://www.pbs.org/wgbh/aia/part4/4narr1.html
And this:
"On this plantation were more than 100 slaves who were mated indiscriminately and without any regard for family unions. If their master thought that a certain man and woman might have strong, healthy offspring, he forced them to have sexual relation, even though they were married to other slaves. If there seemed to be any slight reluctance on the part of either of the unfortunate ones, “Big Jim” would make them consummate this relationship in his presence. He used the same procedure if he thought a certain couple was not producing children fast enough. He enjoyed these orgies very much and often entertained his friends in this manner; quite often he and his guests would engage in these debaucheries, choosing for themselves the prettiest of the young women. Sometimes they forced the unhappy husbands and lovers of their victims to look on."
-http://nationalhumanitiescenter.org/pds/maai/enslavement/text6/masterslavesexualabuse.pdf
and this:
"Many authors of slave narratives agree that Christian slave owners were in fact the cruelest of all masters, including Jacobs, Douglas and Equiano. Douglas refers to these men as the “meanest and basest, the most cruel and cowardly, of all others”. This article enlightened me on many of the justifications that the slave owners believed in this time period. Extreme priests and slaveholders seek out Jesus-like sufferers to use in the crucifixion for their sins. For the Christian slave owner, this comes in the form of the enslaved African American whom they can beat to a pulp as a sign of devotion to the Lord." -http://www.nines.org/exhibits/Violence_in_Slavery
Need I go on?