In "Fahrenheit 451," what does it mean when Beatty says to Montag: "firemen as custodians of our peace of mind"?

Beatty believes that books make people unhappy and and are a source of confusion to them. By burning the books, firemen are insuring that the people enjoy peace of mind because the cause of their unhappiness has been destroyed. Ironically, Beatty's words belie the fact that suicide is so common in Montag's world, that when Montag's wife attempts to kill herself, the emergency response it to send only technicians to save her life. Obviously, it is not books that cause unhappiness, but the entire hollow nature of their society.