If you want someone to blame for the reivisionism, Jubal Early is probably the biggest guilty party. He started the demonization of Longstreet who many feel was a fine general and perhaps Lee’s superior.

And if my memory serves correctly, Longstreet was more accepting of Reconstruction, and this apparently had something to do with his demonization by Early and others.

It says a lot about the power and reach of historical revisionism of the Civil War that someone who tried, at least after the War, to be loyal to his country, was demonized.