Because "Bartleby the Scrivener" is told by a first-person narrator with a strong sympathy for Bartleby, we can't accept all the judgments in the story as reliable. The narrator himself, Bartleby's former employer, confesses not to know what made Bartleby such an unusual employee. He admits that his conclusions about Bartleby are guesses about what caused his employee to decide to "prefer not to" do any work.
At the end of the tale, the lawyer narrator says that if his story has aroused the reader's interest
to awaken curiosity as to who Bartleby was, and what manner of life he led prior to the present narrator’s making his acquaintance, I can only reply, that in such curiosity I fully share, but am wholly unable to gratify it.
However, the narrator does go on to relate a tale he had heard of Bartleby formerly working for the Dead Letter office in Washington D.C. He imagines that dealing constantly with letters that never arrived where they were supposed to go depressed Bartleby. The lawyer writes:
Dead letters! does it not sound like dead men? Conceive a man by nature and misfortune prone to a pallid hopelessness, can any business seem more fitted to heighten it than that of continually handling these dead letters, and assorting them for the flames?
While we don't know if this story is true, and while we know the narrator is biased in Bartleby's favor, we tend to sympathize with him because of his kindness to his employee and his generous heart. However, it is possible to imagine a narrator who would write a very different and much more critical story about Bartleby.