As noted in Part 1, the atheist is not entitled to make an assertion of moral rightness/wrongness and have it understood in the traditional sense: a proclamation of universal, objective truth with regard to a platform of universal objective morality. Only a theist may do this. To drive this point home, a healthy dose of moral nihilism is in order.
To the atheist: You are born with no responsibility to anything or anyone—living or nonliving. You may do whatever you want to anything or anyone, living or nonliving. At the same time no one and no thing—living or nonliving—has any responsibility to you either. Anyone or anything may do anything to you. There exists no moral authority whatsoever to say that you or they are right or wrong. And so, appraising the intrinsic “rightness” or “wrongness” of any action is nonsensical. After death, there will be no consequences at all for anything any of us have done to anyone or any thing. None whatsoever.
For a Christian, the pursuit of righteousness is the pursuit of truth. For the Christian, to declare something as “right” is to say that it is objectively true that this action is right. Because of the influence of Christianity on western civilization, western atheists are inclined to approach morality the same way. But the atheist may not pursue morality as if it is a real thing that he may discover, as if it is a treasure to find, or a righteousness that is true—a truth that is there to find. In breaking with God, atheists must jettison the inclination to think this way. In their dispute with religion, atheists are doomed to confusion and frustration if they continue to play this game by the theist’s rules. Atheists cannot discover morality because it is not there for them to discover.