Have you considered that the inhabitants of Shinsekai Yori's dystopian universe are more knowledgeable about the state of the remainder of the world outside Japan than you? It seems like you're attempting to be pedantic about the setting when you don't possess the information that would allow you to be. You're making a lot of assumptions about topics that haven't been clarified.
For instance, during the False Minoshiro's dialogue in episode 4, it describes an over 600 year period wherein the primary communities of the world were feudal slave empires, completely lacking in the technology you claim to be easily reproducible. The scientists in that era (the ones who archived history and lost knowledge, and who built the mobile libraries) bided their time until the large-scale empires collapsed, then labored to establish communities where humans would be incapable of violence and emphasize sexuality. Knowing that, and postulating that the scientific community was small enough to elude notice, it wouldn't be farfetched to conclude that they primarily cultivated Japan, and so the false minoshiros don't exist elsewhere.
Not only that, but it absolutely hasn't been shown that indirect homicide doesn't trigger death feedback—in fact, it's heavily implied otherwise, else why would a fiend pose any threat at all? If Shisei, the most powerful PK user in Kamisu 66, didn't try to indirectly kill the fiend (only slow it), then it seems logical to conclude that death feedback and conditioning not only come into effect after you actually murder another person, but when you even think about killing with PK. That's why they're so hopelessly outmatched. It's also debatable whether the concept of death feedback is a "stupid system," when their communities have lived in absolute peace until now, with the only disruptions coming from fiends. The only completely nonsensical action on the villages' part is that they don't invest resources into finding the cause of/cure for Raman-Klogius syndrome.