Thank you for your thoughtful response and the link. I don't think you necessarily need to read a whole bunch of theory. I don't think Ito had any criticisms of capitalism or capitalist society in mind when he wrote Amigara, and I'm specifically looking for things that can be construed as reflecting anxieties about capitalist society. I do however think that, being born in 1963, Ito has spent his entire life inundated in modern capitalist society, and his horror stories must necessarily, to a greater or lesser degree, reflect horrifying aspects of living in that society. I think that the link you provided does an excellent job of connecting past themes of horror movies to social concerns that were present at the time.
I just finished reading Enigma again as a refresher. It can be found here for anyone that's interested: https://imgur.com/a/Wht7z
I also did a quick search on DDG just to see if there was any significance to the name Amigara, which I think there must be since the name of the mountain is specifically mentioned while the place ("H—- Prefecture") is left specifically vague. This turned up the fandom wiki page on it https://junjiitomanga.fandom.com/wiki/The_Enigma_of_Amigara_Fault
which mentions both that Amigara apparently means "empty shell," and also offers this explanation of the story's symbolism:
<This story's horror factor is based on the psychological aspect of compulsion. As the holes are "made for them", the people feel the irresistible need to enter, despite knowing the result being death. Famous psychologist Sigmund Freud describes this feeling as "death drive", unconscious instincts that seeks to destroy the individual; for instance, having the thought of jumping off a cliff when near one. This feeling is also known as "call of the void".
<The psychological aspect of this story thus drives its horror. Essentially, it is the story's characters killing themselves - something inherent within them causes a deep urge to destroy their own self. As there are no evil forces/enemies presented in this story, it emphasizes the internal psychological factor - that is, it is possible for people to actually have a desire to harm themselves (such in the case of mentally disturbed persons, and those unable to control their instincts and unconscious, similar to all those that enter the holes in the story). As such, the story comes to explores the innate human instincts of curiosity and destruction (which is also present in Ito's other works) which can, invariably, be the end of themselves.
No citation is given, so I have no idea if this is something some first year psychology student just made up or if it's derived from something Ito said. Taking it as is, I don't feel like it's a sufficient answer on its own to the horror aspects of the narrative. There's Owaki's second dream, for instance, set in the ancient past which suggests that these holes were made by people as some sort of punishment or execution. This externalizes the forces at work from an internal compulsion towards self destruction to outside social forces which apparently apply universally to men and women, and children as well as adults.
There's also the differences in response among the individuals. Yoshida is terrified once she finds her hole, while Nakagaki is pretty cavalier about entering his. There's another young man that seems pretty frantic about entering his hole. You have scientists there to study the holes, as well as rescue crews which attempt to recover people that have entered the holes. It's also stated that those that enter holes not made for them can only go so far in before they're stopped–so the holes are both custom made, and exert a force of their own which not only attracts people to them, but draws them deeper into it once they enter.
So if the "death drive" is a factor, I think it's a secondary one. More significant I think is that the holes people enter into appear tailor made, and their purpose and use are socially derived. The attraction starts when people see "their" shape in the fault on TV, even though there's no way it could possibly have been made for them, specifically. Whether or not it results in their actual death is unclear. In his nightmare, Owaki describes being stretched by the distortions in the silhouette and is alive beyond the point that a person reasonably could be–and the ending suggests that the individual survives the experience but it twisted beyond any recognition of what they were.
The forces at work then aren't the internal Freudian "death drive" but external social forces which individually people are unable to resist. People created the holes as a prescriptive process to reshape other people in their society, which cannot be escaped once engaged with, and which leave the individual a twisted distortion of their original self once they emerge, and which effects everyone in the world.
Capitalist society uses identity in a similar way, whether it's national identity, gender, sexuality, ethnic, hobby, whatever. "Demographics" are human-shaped niches which aren't actually made to fit every individual, but in which individuals are made
to fit, distorting them. Even when engaged with by choice, under the belief that the niche is "yours" which you "fit perfectly" like with Nakagaki, the realization that it doesn't in fact fit perfectly comes only at the point that no escape is possible, that you're "stuck," and at the mercy of forces irresistible and merciless.
Sure, the idea of a spooky hole you can't escape is pretty scary, but I think that's the real root of the horror people feel and which makes the story so famous. It's an experience universal to capitalism known to everyone with an internet connection, of being forced by these inexplicable social forces bearing relentlessly down on people and reshaping them into something no one would recognize as human.