Originally yin yang was about BALANCE in the physical world. Later it became a philosophy and went beyond physical and into metaphysics. Corporeal and Spiritual. The good and evil.
Then Yin Yang began to represent the good and bad in every soul. That each of us must maintain this balance as in the physical universe or face chaos. This is where the yin yang does not agree with Universal Stewardship.
Universal Stewardship teaches balance but it does not infer that the good and the bad are equally distributed in the character of a man. Balance is about Prudence. It is about how we make our choices, because choices define our lives. Most of the times the choices that we make revolve around emotion and not reason. Love and Hate are two opposites and the emotion of FEAR plays a key factor in stabilizing balance. Recognizing and admitting fear but not giving into it is the first step towards stabilization.
Yes there is good and bad in all of us. The one we feed will always be stronger than the other. In certain individuals, families or communities evil pervades. Still, the fact of the matter is that there is more good than bad in this universe.