If religiousness isn't a factor, I don't see how a cruel god isn't arguably more interesting than a social-worker-god. Not that the purpose of this story (which apparently isn't canon and may have been using the name of a known saint as a hoax) would be explicitly in that - perhaps it rests on a motif found also in Job and the Rich man and Lazarus biblical tales, ie that suffering here will be rewarded etc. But it didn't interest me due to religious reasons - I am agnostic.
I once recall being told of an orphan who was taken from the orphanage, briefly, and then returned. In that case, of course, the kid knew that the stay outside would be brief. But some people had questioned whether this was a good thing or not - yes, the kid would know of a more pleasant life for a little bit, but there was the chance the return to the orphanage would discourage - that it would give hope only to take it away.
Multiplying the time, this isn't very different from the immobility story - the analogue of the orphanage is life on Earth, which at some point would stop, but in the case of this one they briefly had a taste of something better. I don't see how it could be argued that it's a more interesting (fictional) story to take a kid to your home forever, than to see the tension a brief stay will create. If it is taken as a real story, of course no one wants the kid to lose, but in fiction you can use tensions and obstacles and categorical denials of this type.