I wanted to write a review of the whole series because it still stayed with me even after finishing and I've been thinking a lot about it.
What's really fascinating to me is that the story is so dark and mature, but the mistakes they make/the obsessions they cultivate are very much because their brains are still developing. It is shown early on that Airi simply changes herself to suit her social environment and cares deeply about what others think - which is why she ends up spiraling when her reputation takes a massive hit, yes, but it's also why she was drawn to Hinako in the first place.
Hinako was entirely devoted to her, which meant that she was safe. Normally when someone realizes this, they let their guard down, relax, and are able to just be themself. But Airi doesn't really know who she is; she has only ever been a response to other people's expectations, and she falls apart entirely when she can't control what they think of her. So instead, her reaction is to go to the opposite extreme - testing boundaries, controlling Hinako the way she feels controlled in her own life.
This is also why she expresses discomfort whenever Hinako visibly enjoys herself during their...uh...after-school sessions. Airi associates that kind of response with other people - the people she's constantly trying to please. In this space, she doesn't want to be a people-pleaser; she wants to be the one in control, she wants to be able to do whatever she wants, and she wants to know that even if she does something terrible, disgusting, horrific, sadistic - she will still be loved and Hinako will not leave her. Again, it's not necessarily that this is who she really is; she has no idea who she really is because she is still just a kid. She is too young to have formed her own sense of self outside of what others expect from her. But all she really knows right now is that she hates people-pleasing but wants the approval too desperately to stop. So the cycle of anxiety and validation and self-hatred continues.
Then we have Hinako, who is relatively easier to understand compared to Airi. It was clear from the get-go that the way she acts after the photos are leaked is a direct result of Airi's behavior. She's just imitating what she has learned. Airi was obsessed with control and only gave her affection in the form of abuse, so Hinako simply reflected that back to her. Airi always told her that she was cutest at her most disgusting, so Hinako learned to view Airi that way, too. She doesn't have any other point of reference; like Airi, she is just a kid.
The tragedy of this story is that these two were just too young to understand how to cope with these things any better. They were never given a chance to learn from it; instead they just kept making each other worse, reinforcing bad habits and driving each other further into isolation. And I've been thinking about this story so much, but I still don't know how they could've fixed it. Maybe if Ichika had been a better person, or if Airi's family had sought counseling (or done anything, really, other than just leave her alone). I don't know.
I can see why people were crushed by the ending, because they all wanted to believe they could get help and get better - that eventually they could stop the toxic cycle and actually be good for each other. But in the end, I think it was just too much to ask of them; how could they possibly break that cycle when the cycle was all they knew?
Anyway. The bug-eating thing wasn't even that weird. I saw a spoiler about it somewhere before I read that part and expected live bugs but they weren't even wriggling around. The piss thing was gross though.