In the struggle between light and darkness, most people would choose the light. Each day, the sun rose, and darkness slowly retreated, along with the monsters hiding within it.
Yet the Anti-Dark Magic Alliance had people like Lockhart. Wearing a knight of light's armor brought more attention, all of it favorable. By contrast, a "black sheep" among white sheep drew plenty of attention too, but was treated as an outsider and rejected by the flock.
Before Harry Potter returned to the Wizarding World, Pomona had a hobby besides sleeping: sneaking off to cinemas in the Muggle world. In a film called The Godfather, the dialogue began while the screen was still dark, before any image appeared.
An Italian American had raised his daughter in America. He had given her an American education and freedom, even letting her date an American boy. But that boy and his friends had ruined her life. Even when the case went to court, they hired a good defense attorney. Their sentences were suspended, and they walked free, leaving the girl's father standing at the plaintiff's table, stunned and looking like a fool.
The apologetic yet smug looks they gave him drove the father to seek out the Godfather. As an upright man, he had never wanted anything to do with someone like him. But the desire for revenge swept aside every other concern. He would do anything for the Godfather if the Godfather would avenge his daughter.
Lawyers worked for money. Even knowing those boys were guilty, their lawyer defended them. It was rather like what the patronum in Expecto Patronum did: both served as shields, as a form of defense.
A Patronus was so pure. Shouldn't it protect the innocent? How could it protect a sinner?
A patron was no lawyer. He was not