If that is indeed your position, they I agree.
The big problem was that there was absolutely nothing to prevent any slave from winding up without warning in the possession of a Legree.
Mrs. Stowe gets a lot of bashing for being anti-southern for her invention of Legree. Unlike most of the bashers, I've actually read Uncle Tom's Cabin.
Given the constraints of the time and the medium, it is actually a quite even-handed portrayal of the institution of slavery. Of Tom's three owners, two are fine people who treat him well.
But due to the inevitable impact of death and inheritance, Tom winds up in Legree's possession, which eventually results in his death.
Legree was not the average southern slaveowner, but then neither were Tom's first two owners. The average was undoubtedly somewhere in between.
Personally, I thought one of the most disturbing sections involved a beautiful young octoroon(sp?) woman raised to the same lifestyle as her white half-sister. In other words, raised to be a typical refined and very religious southern lady. Her father dies and she is sold to help settle his debts. When Tom encounters her she is on her way to be sold in New Orleans to the highest bidder.
The book never spells it out, but the likely highest bidder in such a case would be a brothel. Any institution that allowed such things to even rarely occur legally was an evil institution.