I just realized this; the mother reimu deserves to get her kids eaten since she fell asleep after swearing to protect the little ones. The small children also deserve to get eaten for well, being lured in by an obvious trap.
Perhaps this family of cannibals is not so bad as long as their prey are the stupid and weak?
I mean, the act of kidnapping and eating children is despicable and monsterous, but on the other hand its yukkuri that are getting killed and by their own stupidity at that. So it kind of cancels each other out.
The only regrettable part is that the cannibals get to enjoy themselves for even a moment.