Themes
It is true that we are weak and sick and ugly and quarrelsome but if that is all we ever were, we would millenniums ago have disappeared from the face of the earth.
— John Steinbeck

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Humanity is admitted to be flawed, weak, sick, ugly and argumentative, but the speaker argues that if that were the whole story, we'd have died out ages ago. Our survival is offered as evidence of some deeper strength.
Context reviewed