Tom Wolfe, in Look Homeward, Angel, on the mythology of the South:
And this desire of his was unquestionably enhanced by all he had read and visioned, by the romantic halo that his school history cast over the section, by the whole fantastic distortion of that period where people were said to live in "mansions", and slavery was a benevolent institution, conducted to a constant banjo-strumming, the strewn largesses of the colonel and the shuffle-dance of his happy dependents, where all women were pure, gentle, and beautiful, all men chivalrous and brave, and the Rebel horde a company of swagger, death-mocking cavaliers. Years later, when he could no longer think of the barren spiritual wilderness, the hostile and murderous intrenchment against all new life -- when their cheap mythology, the legend of the charm of their manner, the aristocratic culture of their lives, the quaint sweetness of their drawl, made him writhe -- when he could think of no return to their life and its swarming superstition without weariness and horror, so great was his fear of the legend, his fear of their antagonism, that he still pretended the most fanatic devotion to them, excusing his northern residence on grounds of necessity rather than desire.[The mountain towns of North Carolina are rather more proud of Wolfe than he was of them. In Asheville, streets and auditoriums are named after him.] This attack on the myths to which the South clung -- especially the myth of their warlike potency, really invincible but somehow defeated anyway -- was needed but came before its time.
That myth was seeded in the last days of the Civil War, as Lee attempted amends for his disastrous love of his home State by using his near-mythic stature to end the rebellion, preventing a descent into guerilla war. What Lee did was to blunt the humiliation of surrender, by separating the laying down of arms from the renunciation of the myth of the unvanquished. That myth flourished and spread its roots into the past, so that a lifetime later Wolfe still felt its "swarming superstition" all around him, but Lee's decision cannot be faulted.
The South's resistance to change, and the romanticization of the era of slavery, probably arose following the war. Times were hard enough that the prewar days probably looked very rosy in retrospect, perhaps even for some of the freed slaves -- just as Eastern Europeans are said to be nostalgic for the firm hand of Soviet rule.