This is an interesting way to look at it, to a point of course. Of course, no one is going to argue that the "reality" of Harry Potter is just as grounded in the "reality" we live in as, say, a book about the history of the Cold War. Of course, your point about the "reality" being slanted by the author is a very valid point (and why I used the Cold War as an example). An American-based account of the Cold War may be vastly different than a Soviet account, but both are still "based" on some "facts," although they're both likely filled with "opinions" and perhaps add or omit some "facts" or part of the "reality," but it's still "based on" reality, where (some) fiction is based entirely on a fictitious premise. That said, there are lessons to be learned from fiction and non-fiction of course, and both can be enjoyed if well-written. So, yeah, we may never have an "absolute reality," even in "non-fiction," and we may be able to learn a lot about history/culture/etc from "fiction" (like Homer or Arabian Nights for example).
