this seems to have been misunderstood.
The villagers of Onigafuchi ARE the demons (at least, in the story) and
it was the whole village that would chase down the victim (e.g. the
mother they wanted to eat in the example)
It was worded to sound like the demons were going out and taking
incurable villagers.
The intent of the Japanese is that people would take their incurable
fellow villagers to be cured (when all other hope for them was lost,
presumably).
適当 clearly being used in the second sense of the word here
(その場を何とかつくろう程度であること。いい加減なこと。また，そのさま。) i.e. just doing/saying something
to get through a situation (if anything, doing or saying something
improperly)
