Morality is a fluid thing, not fixed, it's simply a convention shared by the majority of people on what is and isn't a good or evil act, as such humanity is neither, it simply is. Morality exists to enable society, and society exists to promote the survival of the human race.
Things we consider evil now were once considered moral and righteous, example, almost everyone finds the idea of beating (not spanking, full on beating) children abhorrent, yet just a few centuries ago the idea of not beating a child would be considered child abuse, because beatings were considered "good" for you.
Slavery was once considered an every day part of life, now it's consider an evil.
There is no natural good or evil, only what we as people make.