There was certainly a lot going on in this story.
Overall, though, was this about the (after) effects of a devastating alien attack and loss of lives and homes, or was it about why these things had happened.
So much of the story was focussed on characters trying to find a way to survive that I'd mostly say it was about that. But then that ending with the pat message from the alien saying basically, 'We know best and this is necessary, you humans don't know how to live responsibly'
Really? The 'best' option is not just to obliterate most of the human beings but also to completely remove/destroy pretty much all the cities, infrastructure, libraries, laboratories, precious and semi-precious metals, tools, calibration equipment, refined chemicals, books, hospitals for pete's sake, observatories, plumbing, water and waste refineries and processing plants, contact lenses, pacemakers,...........
But at least there are less people now. Granted they have naff all to help them survive (apart from creepy hologram robots offering breakfast) but, hey ho, we will thank the aliens in the future apparently.
I honestly didn't buy it (the message) at all and think the story would have been more enjoyable and provoking if the reasons had been left for the reader/listener to imagine.
The only I bought less than the idea that this really could be an informed, evolved way for a species to act towards us was the possibility that the remnants of the human race would ever be able to forgive them, let alone accept that this was The Solution, let alone actually thank the alien mass murderers.
Maybe I missed something.
Oh, and the reading was very good, too. Shame about the story but good reading.