" . . . For man's anger does not bring about the righteous life that God desires"

Anger is not a completely useless. It is one of an orchestra of emotional instruments with which God has equipped us so we can both enjoy the world and bless it. But along with the rest of our being, our emotions are sullied by sin. Subdued and redirected by Christ, however, they can be used --not as the servant of the ego--but for the advocacy and defense of other persons. That's what God does with his anger.