My problem with prissy moralism in fiction has nothing to do with faith or lack thereof--it has to do with the unidimensional, anti-dramatic nature of moral absolutism. If there is only one way, then the reader can only respond to the narrative in the narrowest emotional sense: with smug self-righteousness. There are easy answers when there should be hard questions.
When I told the woman that noir is the opposite of inspirational writing, I was trying to be provocative. The opposite would be just as limited: nihilism, or whatever. In truth, the morality plays that the best noir stories dramatize engage in the intricacies of moral relativity. They ask questions instead of providing answers.
I recently watched Hard Candy and saw yet another example of just such a moral conundrum: what if the teenage "victim" of an internet pedophile stalker turns out to be the sadist herself, and tortures the supposed antagonist? (Granted, Hard Candy isn't as provocative as it wants to be. The pedophile is beyond sympathy, no matter how "human" and gut-wrenching his performance. Gradual revelations increasingly solidify our distaste for him, polarizing the viewers' reactions. By the time we reach the end, the question is no longer "does he deserve it?", which is the most provocative question; instead, the question is only, "is this girl a hero or a nutcase?," which is a dramatic but all too common cinematic question).
Still, the point is there. Gone Baby Gone (the film; haven't yet read the book; I know, I know) gives us a better example in its last act, one I won't spoil here. Suffice it to say that a question is asked which can never be properly answered. The viewer leaves frustrated, maybe a little angry. Richard Aleas' little masterpiece Songs of Innocence, Michael Connelly's Blood Work and the film Memento all provide moral conundrums about the circularity of crime and its investigation. You get to thinking about it, and you go around and around, and you can't get off.
Frustration, anger, moral relativity. These are the tools of noir, and that's why I think the genre is still so provocative. In fact, it's defined more by these effects than by any motif of character or plot. This is also why "noir" is a somewhat unpopular genre for mainstream readers and viewers. It's an inherently unsatisfying, anti-feel-good genre.
The producer for Hard Candy says in the extras that the job of independent filmmaking is to ask questions instead of providing answers. By contrast, Hollywood trades in Satisfaction, good old Catharsis. This view is a little too simplistic, since numerous Hollywood movies have provided provocative moral conundrums, and all too many independent films provide nothing but exploitation or candy-ass moralism.
I tell my students that (E)motional (M)anipulation of the (A)udience is the main job of the writer, but this isn't as simple as it sounds. The best manipulation is supple and subtle, complex, ironic. It isn't polarizing. Moral positions are used as tools toward that emotional response, since moral engagement is an excellent way to spark emotional responses, from smugness to outrage. So, really, I'm being a terrible moral relativist here, claiming that morality is just a device toward the exercise of EMA. Morality, in fiction, has no pure value in and of itself. It's just a dramatic tool.
We like to believe our moral positions are firm, but nearly every moral "virtue" has its equally virtuous binary opposite, and the clever and provocative writer will recognize how these oppositions can play against each other.
Your average American, for instance, is constantly being tugged between the two polar oppositions of "individual freedom" and "family obligations." We believe in both, passionately, but the one is often in opposition with the other. How many crime novels have played with the oppositions between "truth" and "justice?" LA Confidential is primarily about how justice can only be achieved if the truth is suppressed, and how powerful figures manufacture truth in order to avoid justice.
When moral oppositions come into conflict with each other, the effect is much like hot and cold weather systems clashing together. You get thunder. In fiction, that thunder is called "irony." I think we throw that word around too flippantly, and ignore its power far too often, when we're constructing plots. Irony (the thunderous collision of moral positions) is perhaps the most powerful literary device we have at our disposal.
Unlike most uses of sex and gore and profanity, irony still has the power to shock the reader or viewer. It will always have that power because of how it works: it knocks us out of comfortable moral posturing and reminds us that we're all hypocrites at heart. It holds us over the great chasm of human Mystery and reminds us not to be complacent about our beliefs.
It's not a comfortable feeling, which is why most writing-for-pure-entertainment (including most mystery novels, probably) avoids it. But it is a terribly powerful feeling, indeed.