WWII war criminals are still being looked for sure, but how many Luftwaffe officers have ever been convinced of war crimes? Two. Hermann Göring and Erhard Milch, but for their involvement in the Holocaust, not for anything the Luftwaffe did. Many of the Luftwaffe's top surviving people became officers in the West German Air Force after the war, and worked alongside their former enemies in NATO. People like Erich Hartmann and Gunther Rall.
Maybe Semp's Jewish and lost people in the Shoah, I don't know, but his hatred seems irrational to me.