I couldn't disagree more. Good fiction is more than just entertainment, and you learn as much from it than from a good non-fiction book. Some aestheticians have talked about how you learn from art the same way you learn from more obvious sources. Some non-fiction books are great, but there are a lot of non-fiction books that are just entertainment.
It's not the shelf of the bookshop on which you find it that tells you if you can learn something from it.