I'm with Alex on this.
It does get publicity for the book, and in an ordinary review the reviewer can highlight something in particular which he feels is poor, so this is no different.
And, as I said, I really liked the sex scene in one of the books listed for the bad sex awards - maybe I'll go and buy a copy, cos if I like the sex scene maybe I'll like the whole novel? The pile driver comment was unusual, sure, but I felt it worked.
Sorry, but I do think they are fair game.
However, I do like the idea of a Good Sex Awards too! Why not?
Deb