"he was a madman, and as such would go scot-free even if he killed the lot of them"

   The concept of insanity partly or wholly relieving a person of responsibility for a crime has been a constant and controversial topic of debate since antiquity, finding its way into the practice of various cultures at various times throughout history.  While Quixote often commits numerous acts of violence throughout his adventures, showing several times that he is quite capable of killing those his madness casts as enemies, he is never officially punished or incarcerated for his crimes.

A summarised History of the Insanity Defense at the Online Encyclopedia of Criminal Justice