If only humans make moral codes, then every human-made moral code has equal weight, subject only to one's ability and willingness to impose your code on others.
I'm a Jeffersonian, and I have a high degree of confidence in rational humanity recognizing rationality. I have also learned to expect that irrational humanity will gravitate toward irrationality. Moral codes are not the point; the ability of the individual to reason with clarity toward a positive goal of some kind is the point.