God is the Source of reality, like a Universal Central Processor (CPU); where our realm is made from dense quantum physics.

Because the quantum physics is darkness, it allows for corruption within it; as we see within this realm everything breaks down eventually, and the bigger something is, the more potential there is for it to become corrupted.

Though God could intervene, and stop evils within this realm, it could also cause many things to be affected detrimentally by that interaction; so instead God tries to inspire us to rectify the problems ourselves, so that we become stronger against the darkness, by finding the light within.