I just read an interesting discussion about whether or not a writer must always write from personal experience and knowledge. I had never considered any ethical facet of the question. It always seemed that if you can imagine it vividly and convincingly enough, of course it was all right to use fictional, imagined material and settings; for fiction it's necessary to use imaginary characters. The problems would be in the author's ability to make the imaginary sufficiently realistic.
It struck me that neither the questioner nor the author answering him even mentioned fantasy and sci fi -- two enormously popular genres. The question was whether an author might be perpetrating some kind of fraud on the reader by not having known and/or experienced what was in the story. Does the writer have an obligation the truth that would deny the honesty of fiction? The answer given was that of course, whatever a writer wants to write about is fine so long as s/he does it well enough to make it acceptable in its own context.
Certainly, there are many ethical (not to mention legal) problems with writing and publishing. The truth of fiction is not the same matter for consideration as the truth of reportage or criticism. I can't help feeling it would be beyond tragic if poets and novelists and playwrights had to consider their work primarily in the light of their actual knowledge and first-hand experience. Human beings are animals that can benefit from the experiences of others, after all.
If there is any justification to be found in literature, it must be in writers' ability to offer to better the world in which they write. From the first words, they seek to present work that provides insights, hopes, and recognition of the good -- not only that is with us now, but that readers may envision because of what they have read. That's what "classics" are: maps for the betterment of humanity though revelations, most of which have little to do with actual facts.