You are the one who stated the Iraq war was illegal, not me. You are factually wrong about that.
Your specious comparison to the Holocaust doesn't make you less wrong. Also, I strongly question whether most of the Holocaust was in "full accordance" with German law. Which German laws allowed for the killing of German citizens who were Jewish, or for that matter for killing non-German Jews and Poles, etc? The Wannsee conference and other planning sessions for the Holocaust were not legislative in nature. To claim that the Holocaust was in accord with the Fuehrer's will is quite different than claiming that it was in accordance with German law.
It seems plausible based on your arguments that you do not fully grasp what the category of legal entails.