Coming from this thread. The very classic problem of evil.
But as you know, there has never been a resolution to this problem as every attempt to define it either leads to a contradiction or to something kind of hand-wavy response like "God works in mysterious ways."
Given how foundational this problem is to Christianity, wouldn't it be easier to just say that God simply does not exist? Or that God is not good and omnipotent? And that there is no concept of evil - just biological selection.