Maybe wait a few years. There are stories like that. You don’t know why the hero does what he does, but it gives you something to ponder. If the author gave you the answer, there’d be nothing to ponder. The mystery is the point of the story.
Of course, Bartleby really didn’t come into its own until we had whole college departments dedicated to puzzling over stories like that. Before that, most readers may have been disappointed by the lack of an answer from the author.
Some of Melville's insights are magnificent.