I believe in most cases a military goes to war under the orders of its government, that's political. This was the case in WW2 and in Germany the Nazis were in power. It was quite common back then to address the German military as the Nazis. I know that is what my father called them whenever he made reference to them after returning from the war. It is what this political power stood for and forced their military to do that made them so hated and thus their Name was used by most more often then their Country. i.e.. take note of Winston Churchill's political speeches and his many references to the Nazis. I believe at the point the Nazis started WW2 they had changed so many things in Germany that their political party had more prominence than that of their country. I guess what I am trying to say is this just might be one of the exceptions and it is perfectly justifiable to call it a Nazi sub.