And even if it does not make sense, here we are. We ourself are the proof that things are not true or false just on the basis of our understanding of those same things.
What if an almighty God created the universe without evil but with free-will, and then one angel decided to challange the way God rule, so that God has to let him rule to show everyone whose way of rule is the best?
Simply killing that angel would not answer the challenge, on the contrary, killing that angel would demonstrate that God is a dictator.
Pasted from a reply to another user.