If they are buried in a National Cemetery, they most likely defected and brought secrets with them. Look at Werner von Braun and men like him - they contributed greatly to the US war effort and our post war efforts to control communism.
America as a whole is far too eager to apply our current morality to the past, with no historical background.
I thought they were POWs who was imprisoned in the States who died of natural causes in the POW camp.
Confederate soldier graves, monuments, and symbols should be left alone as well.
Most are the graves of POWs that died while in our prison camps. In the Hampton VA cemetery are the graves of German U-boat sailors whose bodies washed ashore when their boat was sunk.