I came to this book from Sandifer's "Neoreaction a Basilisk", and even though that book is partly a commentary on this one, the commentary is in this case more interesting than its subject.
It may be that different people just have very different susceptibilities to horror, and that mine and Land's have little or no overlap. This brief story shows us two parents worried about their daughter, the three of them going into a somewhat interesting sensory-immersion video game together, and then coming out again (OR DO THEY??? [portentous orchestra hit]).
Even including that obvious final trope, nothing about it struck me as disturbing, scary, horrible, or anything else related to horror, although there were lots of multisyllabic words telling me how terror-inducing it all was. Okay, I guess? For some people?
Various promising elements introduced early on (a creepy stuffed animal, a classmate attempting suicide after the daughter said something mysterious to them) are dropped and never taken up again; perhaps the reader is supposed to fill those bits in, but I didn't see anything in the video game world that would have had much of an effect on a modern youth, except possibly to get them to try a free trial subscription.
Given that I didn't find any horror in the horror story, it's perhaps not surprising that I didn't find the analysis of horror in general, and the horror of Fermi Paradox in particular, especially convincing either. It seems to me that horror, to be effective, must be grounded in the concrete and visceral, even if has a significant component in the abstract and unknown. A fly-covered liver can be horrible by itself; the purely abstract idea that something we currently haven't thought of might remove humanity from the universe sometime, not so much.