I disagree. Nazi Germany took a lot of inspiration in their segregation and persecution of racial.minoroties from Amerocan Jim Crow laws and policies throughout mostly the post-war south. The headquarters of the International Eugenics Society was in the United States, and their policies greatly inspired Nazi ideas of racial superiority.

Also, the Confederacy was way more authoritarian than assumed, far more than the Union was during war time (yes I would call even some of Lincoln's most questionable actions necessary under a wartime government). The south required oaths of loyalty from all of its citizens, the government basically controlled what little commerce they could get past the blockade, and they issued extremely unpopular conscriptions, rationing, and seizure of property (mostly rural poor southerners) that caused some regions to straight up rebel against them (see case of the Jones County uprising). Many of these uprisings were brutally suppressed.

Also, check out what life was like in Confederate POW camps. Or their policy of no quarter against African American Union Troops. And, above all else, let's not forget the inherent tyranny that comes from slavery.