@snood,
I do not know if the outlawing of Nazi symbols was part of the Allies de-Nazification efforts; however, even if it was a voluntary code, it might be to just get on with life and have Germany re-join the family of nations after WWII.
But, where this German outlawing of Nazi symbols is not analogous to the U.S., after the Civil War, in my opinion, there were/are today northern families that do want to honor their families' Union soldiers in Civil War re-enactments, and if the Confederate symbols would get outlawed, what would be said to the northern Civil War re-enactors and their families? In other words, while Reconstruction was less than elegantly done, according to many, the focus of the north was to make the south function as though their seccession never happened and was illegitimate. So, while that might not sit well with some in the south, it would likely be most divisive to say Confederate Civil War re-enactors is verboten, but northern re-enactors are acceptable.
And, are there southern folk today that look upon the Confederate flag as just a reflection of a "dream gone with the wind." rather than some sort of hateful, racist symbolism?
In my northern opinion, where the cause of the Civil War in my 1960's American History class focussed on tariffs, the northern whites wanting a "white west," since plantations left no jobs for white males, I personally think that the strong feelings, on both sides, about Confederate symbols is sowing the seeds of something that can end in a weaker, divided country
I think this in context of many southern whites are still aware that Dixie is a mental place that they live and will not leave when they get a new job. Can't we get past the symbols, since it is like when some northern urban folks might not want "merry Christmas" to be the standard greeting at a store, but instead "happy holidays." It's just divisive, in my opinion.