Forgetting the huge fan base that the book has, which is because it plays to the gnosticism of so many millions of American "Christians" and Jews. Not to mention the "New Agers" for whom the Catholic Church is their bete noir. The intelligensia knows that it is slock, but even for them it serves the purpose of making Christianity seem ridiculous and feeds their delusion that radical Islam cannot possibly be a real threat.
Now that's just scary.
Still, you won't find this novel anywhere but the 'fiction' section. Except maybe on the sale table later on down the road...