This point is made by exploring several examples of bad behavior and seeing how wrong the stories are. The first is the contrasting of a real life Lord Of The Flies scenario vs the one in the novel. The novel has the stranded boys turning into misanthropes who hunt each other down to hurt and eventually kill. It is contrasted with a real life group of boys who were stranded on an island for months. They were found to have continued their friendships, found ways to handle conflicts without violence and validate each other. Other stories include the Kitty Genovese murder case, the Stanford Experiment which supposedly showed people will revert to cruelty when given power over others. Both are shown to have been reported incorrectly and that the lessons to be taken away are diametrically opposed to the legends.
One statistic that really struck me was the low proportion of soldiers who actually fire their weapons. Instead they don't fire or fire over the heads of their enemies. The point is made that the majority of casualties are done by those who don't really see their opponents; situations like bombers who don't see those they unleash destruction on.
This is a fascinating book. The author ends with examples of things that could be different if society acknowledged the best rather than the worst in people. Examples are given of different ways of schooling or running prisons. This book is fascinating and life affirming. It is recommended for nonfiction readers.