I think one of the beautiful things about this story is that it actually describes two contrasting points of view on the matter, and one of them is in agreement

I think one of the beautiful things about this story is that it actually describes two contrasting points of view on the matter, and one of them is in agreement with you. The author spends far fewer words on her sister's perspective (who seems to share the same opinion you do), but I think talking about it less is kind of the whole point -- as you say, the answers are obvious and straight-forward, so there isn't much to go in to. The author herself tries to hold this perspective, but ultimately finds she has a different one. One that includes, among other things, the need to write this story even after "it is finished".