As much as atheists hate to admit it, if there is no God, there is no moral significance to good an evil. For if there is no law, there is no sin; and if there is no sin, there is no righteousness or unrighteousness, and thus no happiness (for happiness cannot exist outside of righteousness) and, consequently, no punishment or misery and, lastly, no God.
Evangelicals try to say that God created righteousness, and then his creations created evil. They fail to understand that one cannot exist without the other; for righteousness cannot exist without evil and it also cannot exist without God.
The one thing that evolution cannot hard wire us for is a knowledge of good and evil, because that requires an intelligence that's not hooked into survival. Evolution, as seen by Darwin, accounts only for instincts related to survival. And if survival meant more than anything else there could not and would not be self sacrifice, compassion, empathy, honesty, or virtue. There also would be no justice, for animals completely lack the concept. They may sacrifice themselves for their young, but only because it adds to the survival of the species. Not because they have a sense of nobility.
Survival rests solely on what one can get away with. Had Hitler, Mao, Stalin, Pol Pot and others been able to get away with what they did and the killing and torture of so many millions of people, then, if there were no God, they would have no one to answer for other than themselves. And it wouldn't have been for good or evil; it just would have been. A million years from now, no one would even remember it or care. And because there is no God, there would be no justice, and if no justice, no punishment. Thus, the actions of all people would be neither good nor evil because good and evil would merely be abstract terms.
Finally, good and evil could not exist except in an environment of free agency. There would be no virtue in forcing men to do good and to desist from doing evil. If God were to force people not to murder or to harm their fellow men, or animals, then he would rob them of free agency, and that he cannot and will not do. He may, on occasion, protect his people and his prophets, but on occasion he's also let evil run its course. Just before Jesus ascended into heaven, he told the apostles they were going as sheep among the wolves and he offered them no hope of victory in this life because he knew of the coming apostasy. In fact, I know of only one apostle who was not murdered for the cause of Christ, and that was John.