I just read something of interest. John W. Campbell, the influential editor of Astounding and shaper of many of SF’s Golden Age authors, once wrote in one of his editorials:
That group of writings which is usually referred to as “mainstream literature” is actually a special subgroup of the field of science fiction — for science fiction deals with all places in the Universe, and all times in Eternity, so the literature of the here-and-now is, truly, a subset of science fiction.
(Quoted in Science Fiction in the Twentieth Century, Edward James, 1994.)
That’s a different way of looking at things. You have to admit there’s a certain kind of truth to it.
So to all the anti-SF literary snobs out there: you’re reading science fiction too! Deal with it. ;)