There are far too many influences on the score that have nothing to do with the quality of the story. The voting, by nature of taking place in the forum where only a tiny percentage of the readers ever venture, creates another skew. The higher percentage of authors who will vote when they read compared to Joe Reader creates another skew. The percentage of same who will dominate the votes here in the forum does it again.
It could be the best thing since sliced bread and haters have bombed the score enough to knock off the H.
It could be middlin' at best but writers here on the forum may be more likely to read it and vote due to name recognition and thus popped the score up because their appreciation of the author translates into bonus points for the story ( even if unconsciously )
It might have score high early on and met nomination criteria, but later readers didn't care for it as much. and like Ogg and Dark said, could've been trolled.