In one of the more interesting sections, it is revealed why The Dark Lord acquired so many followers...
Rowling's wizards, for all their magical powers, look for the same thing from a wizard whose powers are greater than their own.
The leader gives followers a view of the world they want to see: He appeals to their narcissism, telling them that they are good, and their enemies are evil. If they don't have enemies, he creates them. Voldemort, for example, makes enemies of Muggles and "Mudblood" wizards. Unfortunately, these thoughts often turn into actions. The followers believe they have the right to express forbidden desires. They might steal the land of neighbors who are from another ethnic group, or attack the women from that group. In the minds of the followers, these acts aren't crimes. They're defense against an evil enemy.