Except that book didn't have "a similar high-level of comparison to Harry Potter and the Goblet of Fire". To quote the judge: "The contrast between the total concept and feel of the works is so stark that any serious comparison of the two strains credulity"[1]. There is a sort of "know it when I see it" nature that is hard to define, but copyright certainly protects works that are substantially similar even if not straight copies, at least in the US.