Hopefully someone more well-versed in the historiography & memory of the American Civil War can come by and flesh this out, but there are several answers in the FAQ relating to the 'Lost Cause' and the distortion of historical memory in the former Confederacy which you may find valuable. This is a partial list, there are many others worth reading as well.
On the Nazism side, perhaps see this answer from /u/commiespaceinvader. At the risk of self-promotion, I also wrote a brief answer recently on the Historikerstreit of the 1980s and the later stages of the Nazi romanticism myth in Germany.