Book club nominations have nothing to do with nominating the best or most respected books in a particular category and everything to do with nominating what you would like to read. It is ok to enjoy reading stupid books that are wildly entertaining.
As far as Ian Banks only being accessible to people who agree to his supposed messages...well that may be a part of it for some folks, but not me. I just don't like his style His books are a long dull drag from page to page. I see them as having more in common with electronics owners manuals than entertaining novels.
I really wanted to like Ian Banks. I stumbled on the guy while researching another author. The universes that he creates sound well thought out and the novels he writes have spifftastic plot lines, but after reading through three of them I finally came to the conclusion that I would rather get dental work with dull rusty drills than read another Ian Banks novel. Seeing as only one of his novels was nominated (and did not even make the finals), I am guessing that not everyone holds him up all that high.