Just because the Northen States banned slavery doesn't mean blacks were treated well. You need to get over the fact that the entire South was not like in "Uncle Tom's Cabin". This seems to be the image you want to portray.
How ironic. Stowe was sympathetic to the situation of the average southerner with regard to slavery. Simon Legree was a transplanted Yankee,
not a southerner. This
fact was not lost on those who read the book. Its one of the reasons it was so sucessful in changing northern attitudes.
Too bad it got banned in the south.