Actually, she didn't "say" such a thing. She spoke of Adolf Hitler and God being in charge of everything that happens. You might rightly surmise that she included the Holocaust, but she didn't use the words you said she did.
That being said, was the Holocaust any worse than the Roman destruction of Jerusalem, or the Babylonian? Were the murdered in those eras less murdered than in the holocaust? The truth is that God claims to be in charge in those destructions. One would think that God is also in charge in the Holocaust.
God foreknew the Holocaust before creation, yet He created anyway. He could easily have prevented it, or not created the world to go in that direction, or not created at all.
Why didn't He?
We know we travel myopically when pondering the reasons of God; however...
Two possible alternatives illustrate the point: A) He wished man to have free will even knowing the Holocaust would happen B) He caused the Holocaust.
Either way we go with evil in the world, we face quandries; however, the answers led to by determinism are quite worse.