My parents were both translators during WW2. Both worked portions of the Nuremberg Trails. Mom translated many interviews of the survivors of Nazi cruelty and atrocities as well as some of the Germans who had performed the alleged atrocities. She talked until her dying day about the arrogance of the Nazies in the interviews that she translated. My oldest sister was born in Nuremberg.
With the aforementioned background you can imagine what happened to me, the day that I called my oldest sister a Nazi after telling her that she wasn't even an American. First, my Mom spanked me then she washed my mouth out with soap not just any soap but Lava soap. I was spanked again when my Dad got home.
Hardly surprising that you parents reacted that way, Dee! Having to confront, so soon after they occurred, the atrocities and crimes of 'real Nazis' - or to give them their proper name, National Socialists - and the victims who suffered terribly under them. Incidentally, the Holocaust and Concentration Camps in general is an area I have read and continue to read much about. As well as books on the Holocaust in general - detailing the horrors of places like Auschwitz-Birkenau, Madjenik,Treblinka, Belzic and Sobibor along with the terrible atrocities and crimes perpetrated in the East generally - I have publications and memiors, many written by former prisoners and survivors themselves, detailing their experiences in places like Dachau, Sachsenhausen, Buchenwald, Mauthausen, Ravensbruck and Mittelbau-Dora. Gerald Reitlinger's, 'The SS, alibi of a Nation', 1956 is also an interesting and enlightening read! The Schutzstaffel (SS) were one of many organizations in National Socialist Germany who committed appalling and unspeakable atrocities and cruelties and profited enormously from them! 'The Buchenwald Report' a callaborative effort and Eugen Kogon's 'The Theory and Practice of Hell: the German Concentration Camps and the System and Practice Behind Them' are also excellent reads. Kogon himself lived through and survived Buchenwald.
It must have been both harrowing and enlightening in equal measure for your parents to have been present at these trials. One can well understand their reaction in this context!