Not the Bond movie; this has more to do with the original short story upon whose title the movie is based. The idea is that there is a bare minimum of solace or comfort required to keep going, to keep life bearable.
I would suggest that this applies to fiction as well. I doubt anyone wants a story where everyone is happy and life is wonderful all the time. But sometimes the reaction against the high-fructose sweetener plot leads to something equally emetic. I don't think I've ever actually encountered the totally wonderful bit in a book, not even in Pollyanna, which is actually an above-average story, better than the Disney version. I suspect that the Pollyanna defense is really just a poor excuse for putting syrup of ipecac in story form.
In any case, if you have enough negative elements, the story turns ugly. There's enough ugliness in the world without our adding to it; there is enough darkness without our dwelling on it. I would suggest that the negative elements in a Christian story be largely allusive: I already know what ugly looks like and would rather not spend page after page refreshing my memory. But if you can show me beauty, real beauty that isn't just photoshopped ugliness, that is an accomplishment. Or if you're going to stick something ugly in my face, at least do not do so at every turn. Like violence in splatter films, ugliness--be it moral or aesthetic--soon palls, and you have to increase the dosage to get the desired effect. That's called desensitization, and we have more than enough of that as well. In fact, this shows why, even from the standpoint of justifying darkness and ugliness, it's a bad idea.
Supposedly, highlighting such things is simply realistic. But courtesy of desensitization, the highlighting has to be more and more extreme to get the point across, taking us further and further away from that all-important "real life." I was surprised, for example, that no one seemed to notice the character flaws in the guys from League of Superheroes; I kept reading reviews that they were unrealistically good. Yet Tom is sarcastic, condescending, sanctimonious, proud, and a bit cowardly. Even Charlie tends to appease more than he should. But no one noticed these things. Why? Because they weren't exaggerated, and people only notice what's stuck in their face.
Do you call that Art? Then why is it Art to push exaggeration further and further and make reality harder and harder to spot?
Chawna Scroeder posted on the moral and spiritual side of this problem a while back, and I've found her analysis helpful; perhaps you will too.
1 year ago