You'd think so, but that's actually not the case!
This is partly because Jane, despite her trauma, tries to avoid adopting a black-and-white outlook. But it is mostly because Nina doesn't actually idolise Jeff in my AU, at least not anymore.
To give a bit of backstory on Nina/Harley in my AU, she had a pretty shitty childhood that made her very mentally unstable in her teens. As a result, she was very receptive to escapism and harmful coping mechanisms, with a particular focus on gore and TCC. Through that, she stumbled upon Jeff/Killian and became obsessed with him, to the point that she created a blog dedicated to him, where she'd post fan art of him and write "love" letters (as she misinterpreted her admiration for him as attraction). Her blog became pretty popular, which is how Jeff came across it.
Jeff himself is pretty nuanced in my AU, and his actions towards Nina, while horrific, weren't initially malicious. But I'll explain that later; for now, I'll just detail what he did. Essentially, Jeff made an anonymous account and began responding to Nina's posts, which bled into private messaging. They became close friends, all while Nina was oblivious to the fact that she was actually talking to Jeff, and she eventually felt safe enough to tell him about her struggles. Which, as they closely mirrored Jeff's, made him come up with his plan.
Eventually, Nina told her "friend" about a camping trip she was going on. Jeff obviously showed up, revealed himself as her online friend and killed her father. He then convinced her to kill her mother and brother, slice her face and set herself on fire. Afterwards, he brought her to Conifer Down, where she was pressured into making a deal with The Man/Slenderman and changing her name to avoid the law. She ended up choosing Harley, as she also idolised Harley Quinn.
Jane is actually the one who led Nina to revoke her idolisation of Jeff. She didn't do it intentionally, but when Jane met Nina, the first thing they talked about was what Jeff had done to her. At first, Nina had ignored it, but as she matured, she began hating herself for what she had done, and began to understand why Jane hates Jeff so much.
Ultimately, Nina doesn't hate Jeff like Jane does—they still have some sort of friendship, albeit a complicated one. It wouldn't work without the trauma bond it's built on. And she certainly doesn't idolise him anymore. As for Jane, she feels deep pity for Nina and refuses to let herself hate her, knowing she isn't to blame for what Jeff did. That doesn't mean she doesn't hold Nina accountable for both her past and current actions, but she thinks it's pointless to hate her because of someone else.
Also, a small side note that my Jane is neither Arkensaw nor Everlasting. I kept copping heat for combining them, so I just made my own version for my AU.
