People
It is a sin to believe evil of others, but it is seldom a mistake.
— H. L. Mencken
Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The saying sets moral disapproval against a cynical prediction: thinking badly of others may be wrong, yet the speaker calls it usually accurate. That clash supplies the wit. The line presents a bleak view of human conduct through a neatly balanced contradiction.
Context reviewed