
Basically he kills everybody that has no use for his town.
If you have any use, but you break the rules, he kills u aswell.
It is some kind of survival. Not justifying this attitude, but I kinda understand why are them this brutal: less resources, we should kill more people.
Kids could also consume resources, and they cannot produce or do something useful.
Which makes me think about... Why do they need a teacher? Why are the kids inside the village still alive?
Anyways, quite brutal, but still I was kinda expecting that the story followed this way.

If there's kids and they we're not born from the village then it just tell that the doctor is lying about Gyuwon killing his family. . . Some people in the village may make deal will Gyuwon in return of their service/work. "I will work in your village as long as I bring my child/family" something like that
Bro wtf how did he follow him after seeing his kids get crushed to death??? Because he was aftaid?? Fuck that ill go down with a fight if you do that to my kids. And how is the MC even gonna keep caring for him after this? I am all for toxic yaoi but hes literally a child murderer wtf