committing to world-building around a society where human-vs-human conflict is unthinkable will be a challenge. A lot of social dynamics only make sense when the threat of violence is a possibility, especially in a fantasy feudal setting. But it's an interesting thought experiment to follow, where all violence involves outsiders and the in-group is 100% peaceful. What would that look like?
Of course, it's possible the girl is just naive, and human-vs-human conflict DOES happen. Or DID happen. The elf looked sus, perhaps this peace among humankind is a modern thing, and 200 years ago, they were having civil wars and claiming territory like normal? On the other hand, that reaction might have been the elf realizing that if Ginko wasn't killing monsters, she's been killing people.
This series continues to be quality, I hope these themes get explored in the future!