I don't really see a point to this arc. It starts off because Fellow is trying to take over a dungeon to shut it down and try something else in order to mend relations between demons and humans shutting down the whole dungeon system as the ultimate goal. Remme and Demon King are against this for basically no reason just that it would be a shame if it went away. From the reader's point of view, Fellow is basically in the right to shut the system down as it is basically immoral. In a more serious story, the dungeon system would be a tool for advancing a human supremacy ideology. "Yeah other races are strong but if we train hard we can crush them under our boots like bugs."
This arc should be trying to refute Fellow but it's basically not doing that at all. Is what Fellow's doing morally wrong? Remme and Demon King don't seem to think this. Is there a way to improve relations and treatment of demons while maintaining the dungeon system? They aren't interested in this remotely. The only one improving anything is Fellow. If the sole point of this arc is simply to stop Fellow temporarily while not establishing him as an actual antagonist then what's point of this arc?
It's been a while, so maybe I'm missing or forgetting something, but what I remember is that dungeon delving is the equivalent of a sport in this world, like soccer/football. Like football, FIFA is a problematic organization, but that doesn't mean we need to get rid of soccer altogether.
Even if Fellow's idea was fundamentally sound, his execution isn't being done perfectly. This is people's jobs, their livelihood, and he isn't creating a support system or safety net to replace it. So if he were to succeed it would worsen relationships between humans and demons even more because both sides would blame the other for the loss of their jobs, and the disappearance of their world's most popular sport.
