This challenge is to come up with the most plausible way to have the people of the former Confederacy reject the heritage of slaveocracy, planter aristocracy and institutional racism that defined their society prior to their defeat in the ACW. They may retain other cultural idiosyncrasies that make them distinct from the Yankees, but nostalgia for the antebellum social order has to go.
Could the Southern states go as far as redefining themselves as heralds of racial harmony? Something along the lines of "We had our sins burnt away with fire, let us be pure from now on."