I was quite livid about this until the full facts came out.
All he's doing is publishing the Lexicon with no academic stuff at all. So i now think Rowling has the moral right to sue his backside off. I'd rather wait for Rowling's book on the Harry Potter world, as it'll be the definitive version.

It's a shame though, the lexicon is a very good resource for Harry Potter facts when in a pinch.