The whole story is framed around giving value to personal choice and freedoms regardless of potential cost to society. This might be fine on a lesser scale -- there's nothing wrong with wanting your own life and your own actions -- but the story plays it to absolute extremes to the point of stupidity and blind selfishness. One character in particular is condemning thousands to death so she can hang out and have fun with her brother when she is explicitly the strongest being in the setting other than God and could just hang out with her brother after they kill the demon king. (A point they were very near before she just decided to fuck off!) The story frames her as being in the right for doing this, too! Everyone who opposes the idea is painted as either stupid or pure evil like there is no point to the argument of having a responsibility to others. There's no sign in-story that anyone else can take on the demon king, so by electing not to act, she signs a death warrant for all who the demon king attacks. There's no sign the shitty system can be changed, either. The story just goes, "Welp, sure most of humanity will die, but hey, this teenage girl got to do what she wanted so it's worth it right?"
I'm sure eventually the story will culminate in a big moment where the god is the real antagonist and is puppeting everyone to make this shit happen, but that doesn't excuse the stupidity of the story in getting there. Even if the case there is no evidence in the text that is apparent to our characters of it, yet they still act like they are in the right and the narrative affirms them for it. It's incredibly frustrating, this story could have actually grappled with personal responsibilities and when it's okay to quit but instead just lumps it all into "it's always your choice, do whatever you want, more power to you!"
