LU,
The Chazon Ish ones explained when asked about the Holocaust – it is as if an ignorant peasant who walks into a hospitals operating room and sees a team of doctors operating heart surgery – he starts shouting “murderers savages”! Why are you cutting up that person’s body etc! In his ignoramus mind he can not see the big picture’ that is is all for the sake of saving the persons life.
Same is with the Holocaust, we are so far from seeing the big picture that all we see is in hindsight… There will be day when we will all agree and clearly see how each and every action was for the good.