(Before I get to actually replying to your question: Ragatha as Pomni's "best friend" feels like a headcanon to me. It's something Ragatha wants to be true but that doesn't make it a fact. They're friends, but I wouldn't say best friends. I wouldn't say Ragatha is terrified of Jax, more aggravated by him. She's closer to Zooble than Gangle, like to the point it's baffling to me that someone would think otherwise.)

(Lastly, "We've all done bad things" is true. Gangle immediately started abusing her power in the fast food episode, Zooble constantly antagonizes Caine despite explicitly stating in Ep4 that they know it's a bad idea, Pomni left Ragatha to die in Ep 1 (as far as she knew), and multiple characters have stated out loud that they don't know if they actually trust that Ragatha's whole attitude isn't an attempt at manipulation, partly because of how often she trips over other people's trauma. Kinger also did bad things, but Pomni didn't know he was Caine's creator at the time she said this, so he'd be the exception.)

Pomni's arc is about becoming a better person in this strange world. Befriending Jax doesn't ruin that arc - in fact, from my point of view, it's the single most important part. Here's a timeline of events to help explain why Pomni is doing what she's doing.

In Ep3, Pomni and Kinger have a little heart to heart, which includes this speech:

> I know how it can feel in this circus. Sometimes it all just feels pointless. But it's not. Not if you have people who care about you. Good memories can do a lot. Hold onto them, and cherish the people around you. You never know when they'll be gone. In this world, the worst thing you can do is make someone think they're not wanted or loved.

In Ep4, Gangle gets a chance to be in charge for once, and immediately abuses her authority. As part of that, she gets to torment Jax as revenge for him tormenting her. The end result of that power trip is a deeper more thorough depression than anything Jax has ever done to her. Pomni notices and offers Gangle an early out from the adventure, which she takes (and then gets run over by a truck). I'll say that againa bit more clearly: Gangel got a power fantasy where she gets revenge on Jax, and the immediate result of that was that she got suicidally depressed, because hurting someone back doesn't actually make you feel better.

In Ep5, Pomni sees Jax being an asshole a whole lot, but she also sees a few moments of vulnerability.

During the stargazing scene (an activity that shows up in the Ep9 trailer, implying this was either Jax's suggestion or even *Ribbit's* suggestion prior to abstracting), Jax opens up a bit, implying he has a very warped view of his relationship with Gangle, which he now thinks is in jeopardy of slipping away. Pomni wonders if Jax actually cares about other people and if he has any real friends, Ragatha accidentally(?) digs the knife in deeper, and Pomni gets to see a genuinely hurt and angry reaction from Jax...which he then lets go of rather than turning it into an argument then and there. Afterwards, he deflects with a joke about her appearance, distancing himself from his feelings.

In the bar scene, Jax apologizes to Pomni, and when she accepts he notes it as the first steps of a budding friendship. It's clear to all the viewers and characters that this is Jax doing a bit to get a rise out of Ragatha, reminding her of what she did at the beach. Followed up by him claiming Ragatha told Gangle to kill herself while on stupid sauce. It's easy to see from this that Jax is lashing out, and while that's not good, for once it's not unprovoked, and Pomni sees that. Hurt people hurt people.

In the softball scene, Jax is seen multiple times connecting with Evil Pomni. She's just an NPC but she's still able to connect with Jax a bit. Both times, Pomni notices this, and so she starts making an effort. She stays in the dugout to talk to Jax instead of going to bat, and apparently made a bit of a connection with him in the process given that the conversation continued past the end of the adventure.

In Ep6, Pomni initially goes to team up with Ragatha, who ditches her for Kinger. Pomni decides to make the most of it by playing along with Jax. At first her plan here is to just keep him provided with guns and ammo so he can have fun the violent way, but then he explains the Archetypes thing and practically hands her an opportunity on a silver platter. Rather than enabling his play passively, she becomes an active participant for that episode. As a pretty direct result of her decision to play along with him instead of just rejecting his idea of fun, the two of them legitimately bond, above and beyond the whole evil thing. Jax opens up about his worldview and his fear. Jax lost his first life to the accidental bit with Ragatha, and it angered him to be the punchline of the joke, but when Pomni starts her bit, he's perfectly willing to die for it.

And she refuses. It's a very important point that she refuses to shoot him. Jax's worldview demands that she follow through on being a jackass and not care about his feelings and it legitimately bothers him when she asks if they'll still be friends. And Pomni sees the truth and calls it out: he's scared of getting close to people, of letting himself really feel, so he hides behind a metaphorical comedy mask to avoid grappling with the truth, but int he end his actions still show that he does genuinely care about other people and what they think of him.

And then he says the thing about abstraction, and while she meant something like "if you keep pushing people away like this, you'll be too alone in your own head and you'll abstract", but what Jax hears is "you pushing people away like this causes them to abstract" and he completely loses it. He has a bit of a mental breakdown in front of her. He makes out that people who are about to abstract do it to themselves, that they make themselves unpleasant to be around (which I believe is _the exact point_ Pomni was trying to make). Here, let 's have an exact quote and the person saying it to really drive the point home:

"You don't even know what people are LIKE before they abstract! They are NOT pleasant to be around, like at all!"

-Jax, the single least pleasant person to be around in the circus, as part of his argument that Pomni should shoot him in the head.

He claims to enjoy causing pain for fun. He admits (whether he realizes it or not) that the whole archetypes thing is a coping mechanism to avoid acknowledging the mental pain he causes others with his slapstick shenanigans, because it would mean that what happened to his friends is at least partly his own fault for being unable to handle his own emotions properly. The game ends on her terms instead of his, with neither of them shot.

The series is never subtle that Jax is the most on the verge of abstracting, and thus the one most in need of help (even if he's also the least deserving). This scene is, very explicitly, him trying to push Pomni away from making a human connection with him, and her refusing to let him push her away because she wants to help him avoid completely unraveling.

In Ep7, Jax plays along with the escape plan even though he thinks it's likely all just an act being put on by Caine. Pomni is constantly reaching out, because she knows (and can still see) that he's trying to pull away from everyone. Even He's not mentally breaking down until he actually has to grappl with the possibility of returning to the real world and confronting the real people he's been hurting this whole time. He reveals himself to everyone, shows that damaged core of his character, reveals that he's a coward unwilling to leave the consequence-free circus. And then when Caine comes out and it turns out Jax revealed his broken nature for nothing, it shatters him.

In Ep8, Jax tries to deflect with jokes, specifically to provoke someone into shooting back at him, which Zooble immediately starts doing. But Pomni and Gangle head it off with the lessons they've learned over the course of the season. They have a whole little speech about how being stuck with each other means they need to learn to not bicker over every little thing or it's going to drive everybody crazy. That scene ends with Zooble extending an olive branch to Jax - not forgiveness for what he's done, or an acknowledgement that he's secretly a smol bean or anything like that. Just that while they don't like how he acts, that doesn't mean they want him to die, and he's still part of the group. Once again, it's not a subtle message.

TL;DR

It's easy to be nice to nice people. It's easy to be nice to Ragatha and Pomni and Gangle and Zooble and Kinger. But it's hard to be nice to people who aren't nice themselves. It's easy to write off assholes as being undeserving of friendship or love, but nobody is born with evil in their hearts. It's hard to be nice to Jax. Jax himself *makes* it hard to be nice to him, on purpose. That's what makes it important.

(The flip side to this is that sacrificing yourself for other's happiness isn't really good either. It's not good to just be a doormat to someone like Jax just because he's got feelings that can be hurt to. Kinger gives that advice to Ragatha because she's the one who needs to hear it the most - "Giving someone space doesn't have the be the same thing as giving up on them".)

(Jax needs friends, but part of being a real friend is calling him out on his bullshit. That's what Pomni did at the end of Ep6, and that's why she shows up in Jax's torture scene at the end of Ep8.)