It would seem, initially, that Melville was writing for an existentialist or maybe even nihilistic audience. But that would be too simple and it predates most of the more famous existential thinkers (Camus, Sartre), with the exception of Kierkegaard who lived during the 1st half of the 19th century. But one thing about "Bartleby" is its ambiguity, so it could have been written for psychologists, philosophers, religious scholars, sociologists or other academics. Most likely, Melville was also writing this for the everyday worker. The story does seem like a satire of passivity, nonconformity and the mind-numbing quality of many occupations. One of the links below talks about the approach of the Civil War and how the North despised slavery while the Southern politicians claimed the life of the Northern wage (factory) worker is akin to slave labor. So, Melville could also have been writing this satire for the worker as well as the politicians. Anything, or all of these, are possible. I don't know a lot about Melville's biographical info, so I don't know about his politics. But I did read that philosophers William Priestly, Ralph Waldo Emerson and Arthur Schopenauer may have been influences here. This is in reference to their ideas about self-reliance, free will, and that the individual must isolate him/herself from society in order to completely avoid conformity and passivity. In the end, this story is written for everyone who feels stuck in a mind-numbing job or everyday life. Maybe we can only speculate about what Melville had in mind. This story always reminds me of the movie Office Space.