It is a way we reassess our past. We can do that in poetry in ways we can't do in prose.
“Love you will find only where you may show yourself weak without provoking strength.”
“The central ideas of Christianity, an angry God and vicarious atonement, are contrary to every fact in nature, as also to the better aspirations of the human heart; they are, in our present stage of enlightenment, absurd, preposterous, and blasphemous propositions.”