What is the difference between a hero and a villain?
Perspective.
If I were to point out to you a woman who lured a man away from another woman who loved him, you would think she was the villain of the story. However, were I to expand the tale and tell you how she was his wife and had managed to rekindle the man's interest in her, making him leave his mistress, suddenly she is the heroine of the tale.
Do not try and say that this differs on the larger stages of life's arena. It does not. One man's hero will always be another man's villain.
But good and evil, you might protest...
They have nothing to do with heroes and villains. Villains can do great good, even if it is unintentional. Heroes can do great evil, as well, even though their intent is pure.
The better question might be, what makes someone more human, or inhumane?