The South was a backwards shithole filled with illiterates because the few planter elites in the country were too busy growing cotton on the backs of slaves for them to care about investing in any infrastructure or education. The confederacy was formed to preserve a social hierarchy that was favorable to the planter elite and terrible for both slaves AND poor whites. The Confederacy wanted "independence" so they could continue to expand slave territory, preserve their own class position, and keep poor whites in check by maintaining a class of people even lower on the social hierarchy.
And for those of you who bitch about the evil Yankees imposing their will on poor ol' Dixie, why should millions of free people have to have their country's policy shaped largely by a relatively small slaveholding oligarchy? And if we're talking about self-determination, what of the pockets of resistance to the Confederacy within the South, as in western Virginia, eastern Tennessee, and other regions (which are all interestingly regions that are not conducive to large scale agriculture that demanded slave labor). Why should an enslaved underclass have THEIR lives determined by a few slaveholding aristocrats?
No matter how you slice it, it all boils down to slavery. If you think it was about anything else, like some romanticized notion of Southern "honor" or upholding the "true" ideals of the founders (who mostly sought to abolish slavery, albeit gradually), you're either ignorant or disigenuous. If you want to argue that slavery was good because fuck niggers lmao, whatever, you're obviously too brain-damaged to argue with, although i'd respect the honesty.