Man I wanted to like that show because the setting seemed sick as hell but it just won't stop it with the child abuse. very 
vibes
Surprisingly(?) the libertarian elements actually got a lot worse after the first season. After a long time I went back to watch it despite the misgivings I have with some of it because of the setting being so interesting, in an ironic parallel to the story itself, and the setting keeps being interesting but Christ the mangaka and the anime director should both be in prison. Paired with the fact that it has a fetish for horror-tragedy that is just really sickening, it's just a minefield of disturbing elements that is more mine than field.
Surprisingly(?) the libertarian elements actually got a lot worse after the first season.
Literally. The entire story grinds to a halt to revel in the village of frenworld ancap blob monsters who are just the worst in every single way and whose continued existence is dependent on unfathomable horror and suffering. The story fucking loves them.
I was mainly talking about the movie (especially the vivisection scene), but that too. The four-armed girl is depicted in a notably gross way in this regard that even the previous party members (vivisection victim aside) generally weren't. At least, if I remember it right.
I didn't even think of that, my mind just jumped to how the second season revolved around libertarians both euphemistically and literally.
Don't worry, you didn't miss out on anything of value: the vaguely interesting and aesthetically neat setting is half baked as all hell and gets glossed over with even its core conceit ("you can't go up lmao") only ever mattering as much as the author feels like caring about it. I went and did a whole writeup (CW: it's about Made in Abyss, but all the worst stuff is under a spoiler with clearer CWs) a couple of weeks ago about how awful the show is and spent the next day melting down from the psychic damage. I think this line from that sums it up the best:
The whole experience is that of a sort of cargo cult imitation of a dark fantasy adventure story by someone who is fundamentally vapid and brain poisoned. It’s basically just mimicking genre tropes and trying to bring out emotion through showcasing horrific things, but it fails horribly because to put it bluntly the author is too twisted in his perspective and too aroused by what he wrote to do anything but revel in and whitewash the horror.
I'm probably failing to understand something, but I thought the ascending sickness was handled consistently. It only impacts passing the barrier between layers (and does not affect the robot, Reg). I do think it's bullshit that you can go up the "death" layer and avoid death by going back down again within a few seconds, but that's kind of a different problem.
There are several times where it hits a point that's like "wait, being unable to go up more than a few steps would be narratively inconvenient here, so, uh, the curse is just off right here, doesn't happen, we can forget about it for now." Also, even though it's described as being "between layers" in the start it quickly becomes "actually it's all the time, except when it's not," and then becomes even more incoherent where sometimes going up is fine because it's just a little and other times a few steps on a staircase are a deadly threat.
I'm starting to remember that there was that weird exception of the layers not having any effect inside of the city, though I think that one was fair enough given the cause, but I'm also quickly realizing that I should stop unearthing memories because I completely forgot about the birthing thing until I read your review. I will just trust that you've got it right.
I'm also quickly realizing that I should stop unearthing memories
Yeah, that's how I feel every time it gets brought up and all the concentrated awful of it comes welling up. "Cognitohazard" is a meme word but goddamn if it doesn't describe knowing about Made in Abyss perfectly.