For what we need some Absolute Moral Truths set by some obscure greater being? Shouldn't we humans try define good and evil by ourselves, from our own lives and capabilities and things we have read and learned about?
I think if we oppose evil because we've come to intellectual and emotional conclusion of its evilness by ourselves it is by far more pure and more real than some sort of God setting the answers before us.
After all, if I became God and started to define all sorts of crazy **** as good or evil, would you just obey and follow the lead like a sheep? For example I could set something like this
Sacrificing infants during moring is proper way to celebrate my greatness and inherently good.
However, if you sacrifice infants by nightfall you shall be stoned to death for your inhuman, despicable act.
And I was God here, these being definitive absolutes in Universe which I created. Why my creations couldn't come up with more purer, realer morals for themselves?