God created a relative experience, a relative world. He created the realm of relativity, in which all things exist in relationship to themselves, across a grand scale.
It's like saying if God created warm, then why did he create cold? He didn't create cold. In a sense, he didn't create warm either. He just created the thing called Temperature. That's what God created. God created a reality in which everything exists in varying degrees. It is we who have called those things `good' or `bad.'

If we can agree that God did not create warm, but rather, temperature, which is the first level of creation, then we simple look at: What temperature is it? Is it 90 degrees outside? Is it 30 degrees Celsius? What temperature is it? Or is it very cold? And is that `good' or `bad'? And those are judgments that we will make.

I am using a simple example here, to make a point. `Temperature' is the elementary essence, to use this simple example, of the things that are. And so, too, it is on the Scale of Good and Evil. God did not create `good' and God did not create `evil'. Those are human inventions and human definitions. God simply created That Which Is, and it is we who have created `good' and `evil' by calling it that.

By the way, we change that creation from time to time. That is, we call things evil that were not evil years ago. We call things good that we did not call good years ago. So even our scale changes and shifts from time to time. We are, in fact, the creators of our own reality, and we are calling things exactly what we choose for them to be. ~   Neale Donald Walsch