What they mean is, I think, since the game was already pretty grim for the reasons you said ; it was not really necessary to put that kind of ending on top of it all.
The dark was already there and we had to live with it and against it.
For a lot of people, putting this choice at the end felt like a shaggy dog story, like crushing hope for the sake of crushing hope (like real life, one might said).
Especially while robbing us of the choice of saving both at the cost of our life.
I just hope if BaDIK ever becomes that dark, if only for a moment, we'll have the choice this time. The real and final one ; dying for our girls.