The way I see it, writing commentaries & concordances is one of the oldest acts of scholarship. The Mishnah, for instance, is a vast commentary on the legal bits of the Torah & on the then-extant cases of the Sanhedrin & lesser rabbinical courts. I don't see why a concrodance & commentary of Rowling's stories is somehow the same thing as violating her copyrights to her books, any more than the currently extant concordances & commentaries upon Tolkien's books are violations of his estate's copyrights to his books. I think the courts & Congress really need to rethink a number of aspects of copyright, including this one.