Explanation:
1. He meant why was there no swift action from other countries of the world to stop the mistreatment they faced at the hands of the Nazis. So, in a sense, the world was standing by watching the atrocities committed.
2. He believes by doing so he'll be able to help ]reduce the growing anti-Semitism views. In other words, so that younger generations can see why they need to embrace his views captured in his [Mandelbaum's] words, "Anger doesn't get you anyplace. Hate doesn't get you anyplace."
