[xtho]

I personally think it's rather irritiating that you go off on such weird reasoning when somebody offers you a place to stay. The difficulties with that line of reasoning become obvious if you start thinking about whether Turkey or Marroc have been free of guilt during the past 100 years. (Although that would be weird reasoning in itself.)

Anyway, if you had ever been to Vienna you would know that the people there aren't oblivious to the events of WWII. And greeting somebody with Yes/Ja isn't all too unusual in Vienna. I also wouldn't assume a girl selling bread in a Viennoise bakery is necessarily Austrian who speaks fluently German. The simple assumption that she had to be Austrian demonstrates a certain nationalist/racist bias on your part.