[Spoilers] I think I can relate to where Jimmy was coming from, and maybe some of us can, too
Full disclosure, I don't think he's "misunderstood" in any way. Just that his motivation seems very human to me, and we as the player are kinda "supposed" to put ourselves in his shoes because we can all make mistakes, what matters is how we react after.
Being one of the "losers"
I really liked how the characters in the game are portrayed as sort of "losers", making them a bit more realistic and relatable. Anya failed med school (multiple times, Jesus), Swansea is a relapsed alcoholic, and Daisuke is just this irresponsible, sort of stupid young guy. And then there's us, the player, and our best friend, the most capable and promising out of the bunch, who is ready to move on from the band of misfits onto better opportunities.
So now, just as we've started climbing the corporate ladder, we're then "demoted" to be with all the other "losers" in the jobless club, while our successful friend is bidding us a tasteful farewell and moving on. Fantastic news, makes you want to rage, doesn't it? And then there's our sins coming to bite us in the ass, when people learn of some unsavoury things we've done. That's an even bigger hit to the fragile ego, after being reminded of how we "struggled" back on Earth, that one really hit a nerve.
It makes sense that someone would make a leap in logic to avoid cognitive dissonance (This is hurting both of us! So by crashing the ship, I'm actually helping you save face as well!) Instead of facing the inevitable blame, shame, and guilt head-on—which is uncomfortable and scary—it’s easier to just delete, wipe, clear everything out, as if it never happened in the first place. Humbly accepting the following eight months of judgment, and the resulting docked pay and public shame? That would take a lot of humility out of someone.
Guilt slowly eating you up
Now, personally, I think Jimmy still felt the guilt for them all in the end, especially considering that he does indeed shoot himself. Haven't we all experienced doing something stupid, then feeling that nasty gut feeling of absolute dread and regret, then having to roll with the lie because confronting the truth seems too scary? And then it all piles up, and then being forced to face the result of your actions is really painful by then? That's how I imagine he could've felt, and accepting responsibility felt impossible at that point.
As to why he apologized to Curly, I think is because it's the only person who understood Jimmy and still cared. Also, guilt and realization kind of takes time to mount up. And Curly "following" him around, watching him constantly; I think Jimmy genuinely does feel guilt over hurting his friend, being cruel to him. He probably, would be my guess, feels guilty about everyone else too, but he's not as close to them and saying "sorry" to them wouldn't feel as satisfying.
Still, Jimmy's got a self-centered version of guilt, not so much focusing on how Curly (or anyone else) feels, nor really acknowledging that he squashed all of Curly's aspirations out of petty jealousy, and lied and avoided the reality all the way through. I dunno about others, but I've definitely felt that way before. It's a intentional conscious choice to try and empathize with others and put yourself in their shoes, instead of viewing it through a selfish lense (oh no, this shit makes me look bad). It's a difficult reality to accept and doesn't feel nice at all, especially when you've done something really reprehensible.
Why did he go schizo
I was trying to understand why he was seeing so many creepy things. But then I remembered, that's how guilt or shame manifests in my dreams too — something unsettling and scary, because accountability is scary. (For example, I've had a dream where I forgot to feed a cat for days, and its corpse came to life to talk to me and scold me. I don't own a cat, but I guess it's a representation of other things I've forgotten to do that led to bad consequences.)
He basically didn't save Curly but "saved" himself in the end from the embarrassment
I couldn't exactly understand how Jimmy still felt as though he'd somehow fixed something by the end. I feel like the ending was the moment when he should've felt the most ridden with guilt, and ideally disillusioned and seen everything clearly at last.
But even in the end he completely disregarded Curly who, I believe, was begging to die at that point. I'm not sure if "why don't you finish what you started" relates to Jimmy's desire to frame everything as an accident, or if Curly suggested getting into the utility room and putting them both in cryopods, but I think he meant he wanted to die though.
But Jimmy still said "no" to that, because he wanted to fix things his way for a chance to feel good about himself amongst all the guilt. I can sort of understand it, but for me it'd be more merciful to actually listen to Curly and end his suffering, and ideally put myself in the cryo chamber because then I can actually tell the whole truth about what happened, in case of being found. It's uncomfortable and scary, but that's what taking responsibility would mean to me, if this was the only choice you could make in the game — save Curly or save yourself.
All in all, though, this could be completely off base here. I just think that this behavior isn't solely exclusive to people that are "monsters", but also those of us that can be a bit irresponsible, maybe cowardly in some ways, not very successful, jealous, afraid of our mistakes, and this is just a showcase of how far it can spiral if we don't take a hard look at ourselves. I think in that way, those of us that relate to those things can also relate to Jimmy. Not the rape part though.
Notes: Honestly, it might be a coincidence, but I think Jimmy "stole" the idea of killing himself from Anya, and basically he relied a lot on Anya throughout the game which was interesting. She was the one who suggested the code scanner and where it could be found, or where to find additional sanitizer. And honestly how "gently" she was nudging him on to take responsibility by feeding Curly his pills was kinda genius, which he was getting so mad over cause WHAT DO YOU MEAN I HAVE TO DO IT?!?! 😰 You b-baka... Okay I'll stop.