@sssr
I think this explanation fails to account for many things that feel plot-relevant. Not that the others ones are any better, though. There are still many things that are unknown and can't fit tidy into the theories.
This is what we have thus far:
[ul]* The facility kids all have some sort of severe genetic modifications, giving them superhuman abilities. One of the chapters explicitly says Tarao was very strong and the other said his body was "made to be immune to known diseases", so he was probably one of the better specimen.
* The caretakers don't know the truth behind man-eaters or the corresponding disease. Based on their conversations and reactions they never knew how to treat Tarao, clearly hadn't seen a man-eater core before, and still don't know how to diagnose the others. This, for one, clearly proves that at this point they know less about man-eaters than Maru, Kiruko, or Dr. Usami.
* Maru's backstory doesn't seem to have any direct connection to that particular facility, even though he has the same enhanced body capabilities as the kids there. He was never mentioned by the facility kids or staff, either.
* We don't know what the connection is between Kona's drawings and the corresponding man-eaters. The staff don't seem to pay them any mind.
* We don't know what the fuck those "babies" are, but they clearly aren't human. Anatomy doesn't work that way.
* We don't know what the deal with Asura is, who mailed Mimihime's nude pic to Shiro and then deleted it, who hinted at the outside to Tokio, and how this is all connected.
* We don't know what the drug intended for Tokio does or what Maru has to do with it.
* The facility kids are explicitly prevented from learning anything about the outside world, to the extent that most of them don't even know there
is one (it was confirmed early on that Tokio coming to that conclusion was an unfortunate accident rather than something the caretakers expected to happen). This suggests they were never intended to ever see it in the future. They're also all very young, barely in their puberty. In one of the chapter's, a "pick up date" was mentioned, so they were probably bred for that purpose (organ donors? breeding partners?).
* The doctor that transplanted Haruki's brain in Kiriko's body was said to have been studying man-eaters. It might be that he was on to something, and the operation was part of his ongoing research.[/ul]