The One True Purpose of Writing, According to John Steinbeck

"There is one purpose in writing that I can see, beyond simply doing it interestingly. It is the duty of the writer to lift up, to extend, to encourage.

 

"If the written word has contributed anything at all to our developing species and our half-developed culture, it is this: Great writing has been a staff to lean on, a mother to consult, a wisdom to pick up stumbling folly, a strength in weakness and a courage to support sick cowardice.

 

"And how any negative or despairing approach can pretend to be literature, I do not know."

 

— John Steinbeck, Journal of a Novel: The East of Eden Letters

What do you think? Is Steinbeck right or a little off? Is helping others out really the one true purpose of writing? Can something that's negative or despairing be literature, or is it something inferior?