Naive cynicism is a cognitive bias, and a particularly tough one to argue against. It's blamed for all kinds of trouble in the real world. Could it also be a problem when creating fictional worlds?
Naive cynicism basically means we tend to think that other people suck far more than they actually do. It's at work in business partnerships, romantic relationships, and even, arguably, in social policy. Ask two people estimate how much work they do in a partnership, and they will both say they do the lion's share. That's not naive cynicism; naive cynicism kicks in when both people are asked to estimate the amount of work their partner thinks they do. They almost universally underestimate the amount their partner thinks they contribute. This happens in friendships, in relationships, in business. Thanks to knee-jerk cynicism, we consider other people black-hearted scoundrels, when they're only a little self-centered.
We assume people are worse than they are, and have worse intentions towards us than they do. The trouble with this thinking is, whenever the idea is challenged, it's easily dismissed by pretending that anyone who thinks otherwise is out of touch with the real world, and its ugly truth. Of course the people we lock up forever are trying to kill us. Of course a rival government is just making empty promises to get us to drop our guard. If you don't think so, you have no idea how bad other people are.
Whether this is true in the wider world is a matter of debate, but it's certainly happening in the world of sci-fi and fantasy. Thirty years ago, the most famous sci-fi (and arguably fantasy) trilogy in the world included a cosmic source of pure goodness that people could tap into by controlling their own urge toward hatred, a group of dedicated and loyal freedom fighters, and the whole thing wrapped up when the bad guy decided he'd rather bond with his son than see his cause win. Today in genre fiction, everyone is corrupt and you're lucky to make it through a wedding alive.
This isn't necessarily a criticism. Each successive group of writers naturally write variations on the themes explored by previous generations. Giving a genre more complex societies, and more complex characters, isn't bad. Moreover, fantasy and sci-fi genre writers aren't necessarily trying to reflect reality. The relentless darkness of their stories works as a theme and an aesthetic. The problem comes when we confuse the aesthetic with reality, and say any departure from it is unrealistic, instead of merely unfashionable. Pure evil is no more realistic than pure good. Could we use a little more hard-nosed, realistic optimism in fiction these days?