Just like all those good little NAZIs who were tried at Nuremburg. This man was able to recognize an illegal order and he refused to follow it. That was what Nuremburg was all about.
Rules of war allow for a person captured in the battlezone out of uniform to be tried as a spy, not treated as a prisoner of war. His uniform was that issued by the United States of America. No american military person can be ordered to be a spy.
Um, if it was an illegal order, why did he get a bad conduct discharge instead of the metal of honor?