The Bible was written by men, not God.Correct. It is not virtuous if you are forced to be virtuous. He let's us find our own way.
Um, really?
Do you actually READ your bible. There's a whole shitload of things that God said you SHOULD be killed for doing. Like picking up sticks on the Sabbath or having the Gay sex or just having the bad luck of having a torn hymen on your wedding night. (And your parents were expected to help stone you to death!!!)
So God let us figure out on our own that slavery and genocide were wrong, but man, you were totally on your own if you accidently busted your cherry doing hard labor on the farm.
Not to mention your interpretation of it may be as flawed as their interpretation of God's revelations.