If you want to feel sad, angry, and hopeless over the nature of the human condition, watch these three segments (about 15 minutes total) from a BBC documentary about aggression. In it the film makers replicate the infamous Milgrim Experiment wherein a subject is persuaded to inflict extraordinary harm on another human being by the mere presence of an authority figure.
Thus it is sadly not inconceivable that people (normal, fine, decent people) when placed in certain situations are all too capable of actions that would cause the sun to grow cold with horror.