Neil Gaiman's blog has a comment about Terry Pratchett's letter to the Sunday Times, in which he points out that the Harry Potter books are definitely fantasy. And as for the claim that JK Rowling is the first person to subvert fantasy, well, er, hasn't Terry Pratchett been doing a splendid job of subverting the fantasy genre for last 34 years???? However, as Neil Gaiman points out, it's probably sloppy journalism rather than what Joanne Rowling actually said.
Most people seem to think that SF (and most other types of genre fiction) is beneath their notice, and would be embarrassed to be seen reading an SF book in public. Now I must admit that I would be embarrassed to be seen reading certain types of genre fiction (romance, detective fiction except for Raymond Chandler, westerns), but in the case of SF I think it's part of the general prejudice against science (someone once laughed at me for reading New Scientist!)
I must say that too much of fantasy is concerned with some kind of pseudo-medieval world, but by no means all of it. I'm not sure what genre Neil Gaiman's American Gods fits into, but it is very contemporary. And though his Stardust is set in the land of Faerie, it totally subverts all the tropes, and is definitely hard-edged stuff. So evidently either the journalist who wrote the article is putting words into Ms Rowling's mouth, or she hasn't read much fantasy, and should definitely read some of Mr Gaiman's and Mr Pratchett's fine productions before making sweeping pronouncements.
EDIT: Good comment about it on Karen Traviss's blog as well, in which she also points out that Ms Rowling was probably misquoted. (I have personally been grossly misquoted by a journo, and so has my partner, so I wouldn't be surprised.)