When we last left our group of basically well-meaning schoolchildren, they had cornered a precursor artifact data repository and were threatening to torture it to death unless it revealed its secrets. I still call them basically well-meaning, because hey, it’s not like they were hurting people, just knowledge-robot-demons. (It turns out that in the demon-haunted world of Shin Sekai Yori this distinction has the force of a physical law. But we’ll get to that later.)
The kids start off asking about the demons that haunt their world, because after all that’s what they had intended for this trip to be about, but the conversation quickly turns to history, and an explanation about how “ancient civilization” (in other words, our world of 2012 that’s ruled by Modern Liberal Democracy) turned into the current demon-haunted world. Apparently, researchers in Azerbaijan unlocked the secrets of psychokinesis and created a class of PK users that made up about half a percent of society. Some fraction of these PK users gave into their base impulses and took selfish actions which destabilized society.

God, fictionalized science fiction societies are adorable. (Note: the speaker is one of the kids, not the library robot demon.)
After the shakeup in society settled down somewhat, there were four main groups surviving: the “slave empires” that were ruled by powerful PK users and sometimes set citizens on fire for no reason, the hunter gatherers without PK that lived on the edges and tried to avoid being enslaved by the empires, the bandits with PK that preyed on the people on the fringes of the empire, and the scientists who were holed up desperately trying to keep the light of Progress and the Accumulated Knowledge of Mankind alive. But even this four-fold system turned out not to be stable, at least locally. After a particularly bad emperor set particularly many citizens on fire, the local slave empire collapsed, and the local scientists had to swoop in to pick up the pieces.
Now, you might have thought they would do this by installing a Modern Liberal Democracy as laid out in the ancient traditions, but that would be naive. After all, Modern Liberal Democracy had been tried, and it had collapsed when faced with the prospect of a class of PK users. And besides, it would be an old idea, regressive, like the U.S. installing a King in whatever two-bit country they overthrow next. What was needed was a truly progressive approach to the challenges of the day.

Those hippie-dippy scientists! Haha!
They wanted to create a society of love. Among their methods of doing so was to introduce competitive PK sports into the school curriculum and “eliminate” any child caught cheating at them, as we saw in episode 2. Another method was to introduce an automatic biofeedback loop that would hurt or kill anyone who used their powers violently on another human being. The mystical society that the children grew up in was deliberately designed by social scientists and psychologists to be, if not a utopia, at least a society that could survive having the means to destroy itself. And for what it’s worth they seem to have succeeded! Their society seems to be basically sort of ok in a lot of ways, so long as you aren’t a filthy cheater or not very good at PK. The library monster never explained why the children who can’t do PK disappear. Is that part of the system too, or do they just get eaten by demons?
Maybe if the database daemon had been allowed to continue, it would have explained this. But just as it was getting to the good part, a powerful PK user appeared and set it on fire. He was a high muckety-muck in the church, and he was really upset that the kids had wandered away from where they were supposed to be and started talking with demons.

Would you say this violation makes you… platinum mad?
As punishment for their heresy, he sealed their magical powers and began taking them to the temple, for Final Judgment. Along the way, we got a demonstration of the dangers of the wilderness and also of the powers of a truly skilled wielder of telekinesis when the party was attacked by ratpeople brigands with crude bows and clubs. The monk just cast Tornado and wiped out a whole band of them. This was disturbing to the tenderhearted girls, but the boys thought it was awesome. So much for a society of love, eh? I’d say “ratpeople aren’t people so who cares”, but the massacre actually triggered a mild version of the self-destruct reflex in the monk, because ratpeople sort of look like people, and he used his TK to kill a whole bunch of them. So now they’re in trouble, because the kids don’t have powers and the adult has to lie down and wait for his body to stop trying to kill itself and they’re out in the dangerous wilderness and OH GOD LOOKOUT A BOMB DOG DEMON and then the episode ended and left us with a dumb cliffhanger.
So. Obviously the most interesting thing this episode was the first half, where they explained the backstory. It was really interesting! Now, politically speaking, I identify as a progressive, or maybe even as a liberal. And the show’s future history can basically be taken as a condemnation of progressivism. Yes, you can argue that the scientists did what they had to to create a society that could survive in the demon-haunted world. But the society they ended up with is sinister, and they hacked people’s bodies to introduce involuntary self-destructs, which seems sort of unkind. And anyway, it’s not clear that they have actually come up with a society much better than the slave empires they replaced. The ratpeople seem to be sort of replacements for the slaves and bandits of the old society, and the disappearing children seem to be as bad off as the incinerated peasants under the old system. And anybody that would take away the power of humanity for someone just for listening to heretical talk from a rainbow book tentacle demon has to be evil, right?
I know I frequently downrank shows for disagreeing with my politics. But the thing is, when I say that, I’m being polite. What I’m really downranking them for is for having freakin’ stupid politics. Shin Sekai Yori isn’t that. It may be taking a stance against the progressivism I hold dear, but it’s taking a stance it can back up. It’s not saying progressivism is pointlessly, purposelessly evil. It’s saying, here is a situation, here is the progressive response to this, and here are the justifications for that response, but you can see that it has this and this and that bad effect and children are being fed to cat demons. And that’s great! If you can back it up, I’d much rather hear you weigh the pros and cons of Modern Liberal Democracy versus German Militarism, like Legend of the Galactic Heroes did, than listen to another proper progressive lecture me about how great Universal Healthcare and Not Starting Wars is. I’m not a choir member who likes to be preached to.