It's not about how psychology works, it's the unknown pull to go in. AFAIK our physiology doesn't turn us into weird gangly monsters if you put pressure on our neck and limbs, but you don't seem to have a problem suspending your disbelief in that way, at least not in any way you mentioned. I think the urge to enter the holes is framed as almost supernaturally strong. Maybe it was written with a basis in the idea of intrusive thoughts, but its more like a cognitohazard that enters your mind when you see "your" hole that compels people to climb inside. I find the horror comes more from the idea that you might find a hole that you become convinced is yours and would travel all the way there just to enter. (And then the claustrophobic darkness too)

Consider this, then. We understand how psychology works and why this situation is complety outside of any realm of possibility. Yet it is happening anyway. Consider that there is something out there, something external, something unknown, that we aren't even aware of yet that can have an effect on the human brain beyond the scope of our understanding or capabilities.

D&D has mindflayers that command a powerful control of the psyche. In that world, it is a logical reason for unusual or impossible behaviors. Harry Potter has the imperious curse as a logical way to accomplish something similar. These don't work in the real world and we have no real world equivalent.

But, the things in those worlds weren't always known about. There had to have been a period of discovery. Same with our reality. There have been many things we never knew we never knew until they were discovered. Applying logic to these situations with the knowledge of the time made it harder to understand or take seriously because we didn't have a concept yet for what it was. Yet it was there.

The fault represents that unknown both in knowledge as well as understanding. It isn't meant to be taken literally as "This thing can cause supernatural brain control." Rather, it is playing on that concept of discovery of the unknown. The hole we as humans must dive into to understand the world around us. The comic doesn't reveal the reason for it. But isn't that the very nature of exploring the unknown? We are driven to it to fulfill a need.

Sure, it could be that there is an unknown "thing" the comic never reveals, something left to our imagination to fill in the blanks which can often be a lot scarier than anything we can come up with. But it is stirring those thoughts of curiousity to find the reason, the source. The hole is considered "my hole" not because it was made for us, but because that is our personal passion, our special interest, our allure for discovery. And through it, you are changed.

Suppose it's magical and not scientific then

No need to make something up? You hVe to be trolling. What a dumb thing to say. "No need for fiction to exsist" is basically your statement

If you find a hole hidden under geological eras, and it was made just for you and you knew it... you wouldn't feel tempted at all to just... take a step in... a unique hole unlike any other in the world, this one welcoming you like your own shadow with its depths... and confirm that someone really did carve out your exact silhouette?

It's certainly something I could imagine happening in a dream. Like my recurring dream of driving off of bridges.

There is a Buddhist element of reincarnation going on which might be lost on some foreign audiences, but the feeling it is trying to summon should be familiar - a strange familiarity of something that should be unknown to you, an inexplicable intuition, something that feels like it could be from a past life, a premonition, deja vu.

If none of this is relatable to you, that's okay, but it is relatable to myself and many others. Hopefully you don't have recurring dreams about driving off of bridges, either.