"Jesus would rather kill, not marry, gay people" - Franklin Graham

[polymath257]

I'm saying that if such a being existed, then its values may or may not be in line with what humans need, so we need to figure things out for ourselves.

And that it is immoral to do otherwise.

You are erecting your own version so you can knock it down (there is a phrase for that). Remember, we are not discussion whether the belief is true, we are discussing what is that belief--because it is constantly mischaracterized. The belief is:

1. God exists as the greatest conceivable being. 
2. God's character is the standard for Goodness (from 1)
3. He has revealed himself in nature, scripture, the person of Jesus, and as the Holy Spririt
4. We were created for a purpose (from 3)
5. A big part of that purpose is wrapped up in morality. (from 2 and 3)
6. Our morality is based on God's commands (from 5)

There is no room for your "figure it out for ourselves...immoral to do otherwise". That is your belief--not a Christian's belief.

Precisely why the Christian belief is immoral.