Theologically, just because we believe that every life is like a universe, the Holocaust does not create something new by way of theological dilemma.
The theological dilemma is born in Genesis, Chapter Four, where there is sibling rivalry between the first two human children, and Cain kills Abel. God knows that Cain is planning to kill Abel and warns him in advance, and yet nonetheless Cain goes ahead and kills him. So why did God not intervene then? The question that we raise about the Holocaust could be raised right then.
There’s nothing new theologically about it, but in human terms, obviously it is completely unprecedented. The only possible precedent would be that long trajectory of history of Jewish revolts against Rome, beginning with the Great Revolt, 66 to 73, then the Kitos Rebellion, which was throughout the diaspora as well in the years 115 to 117, and then the Bar Kochba Rebellion of 132 to 135. Put those three together and you get, pro rata, almost a comparable loss of human life. The Jewish people were smaller in those days, but that almost extinguished the flame of Judaism. That’s the only precedent I can think of.