I disagree with all of you (sorry it’s so long)

I don’t think we can view it from a civilian standpoint. This whole town runs itself like a military base camp but instead of perceived democracy, it’s pretty much a dictatorship without gyuwon BEING a willing dictator. He doesn’t like any of those rules either but when you’re in an apocalypse or you’re fighting against an enemy thats not going away, you HAVE to change your morals.
Also it’s unfair to say he’s not a green flag when he doesn’t even understand what morals are to begin with. It’s like calling a baby immoral for hitting someone but they don’t know that hitting someone hurts them. They have to be taught a better way.
Personally, the choice to kill the person who stole medicine is the right choice. Not just for gyuwon but for all the residents who don’t want to go back outside. He even explained it. The medicine is set aside for the “hounds” aka people who are on the outside and bring back supplies. If one of them dies, supplies would be lessened and then someone from inside the village would need to go outside to compensate. Keeping the medication for them is smart. The father could have easily asked gyuwon if he can have the medicine and in exchange, if the hounds needed it, he would offer himself to go in their place. Gyuwon would have seen that as an okay deal since balance is still being upheld.
As for him killing people he didn’t need outside, in his mind (as we often see him doing), he’s putting someone out of their misery. He doesn’t understand what a life is valued at because all his memories are from when the apocalypse started and humans and the maggots look similar. How can you value human life when a maggot, a near human, is killed without mercy? He views killing as survival not as a crime or a sin. Just how most of us view killing animals for food a part of survival and not a sin or crime or how we view what the militaries do as something good and to be proud of instead of the mass genocide it truly is. Most of what militaries do is kill each other and civilians in the process. What makes gyuwon any different to what our militaries already do? This whole book is a metaphor for our own society and that’s what ALL apocalypse based media is about. You can’t have a double standard of “don’t kill humans” and also “please kill things that look and kinda sound like humans!” And you can’t have the double standard of “please have morals!” And “you don’t need to worry about morals as long as you keep us alive.”

He may not be a “green flag” in the traditional sense but he was raised to be this way by the villagers not the other way round. Any one of them could have taken the time to educate him or better yet, could have stayed on the outside if they were so dead set on their morals. He’s a “green” flag because he tries to protect those he cares about, he thinks big picture and makes sure the whole survives even if the few don’t, he genuinely cares and loves the teacher even if he doesn’t realise it yet not to mention he’s WILLING TO LEARN. Cesare from roses and champagne isn’t and yet everyone (including me) loved him. Why not gyuwon who has already been established to have the mindset of a child who doesn’t know anything?