"However, at least we can agree that the answer to the question in the Topic is:
Because no one (BORN AGAIN Christians excluded) can agree upon the definition of what is GOOD."
It does not follow that we need a God to agree on a definition on what is Good. The reason I say that is because no one can agree on who God is or what he wants. Some people's version of God wants human sacrifice, some want martyrdom, some want love and peace. Christians cannot decide on what is good even when they follow the same God and guidebook. For instance, the definition on fornication varies widely between one Christian denomination to the next.