What is the dilemma for Simon Wiesenthal when Karl asks him for forgiveness?

Simon could not bring himself to verbally forgive Karl the atrocities that he and the Nazis committed against the Jewish people. Simon had lost many of the people he love.... friends, family, and others within the camp. He had no wish for revenge, and he felt no satisfaction in Karl's circumstances..... he simply couldn't the past or allow Karl the peace that so many Jews would never find themselves.