You know what Jackie needs? To be friends with Fitch Cooper. Not because he's so great or because he has anything to teach her exactly, but because his complete obliviousness ends up in the same place as Eleanor's total loyalty. You can bitchslap him five times and he'll still sit down next to you like you're even friends, and start talking about hair products. She pretends that's the kind of friend Eleanor is, it's a game they play, but it's totally not true. With Coop it really would be true, and all you have to do is stroke his ego twice daily, which she and Eleanor do for each other all the time anyway. And it's fine, because there's no power differential. Eleanor's a doctor, like Coop, and a brat like Coop, but because she's a woman it's not gross to treat her like a housepet, which is all either of them really want.
But the big secret of men is that they are incredibly easy to work, because they only have a few buttons; Jackie's power and the wonderfulness of her lies in her absolute inability to push those buttons, and it's why Gloria loves her so much -- not to mention Eddie and Kevin -- but honestly it makes things so much simpler. Maybe that's the problem: Maybe Jackie hates Coop the same amount that she hates Sam because they are both questions she cannot possibly answer without losing everything that makes her Jackie.
Jackie knows what women are, so she knows Eleanor's secrets and she knows Eleanor will never surprise her, either by grabbing her boob or making any of the other white male power plays Coop makes daily without thinking twice about it. She can fight with Gloria all day long and never get scared or feel vulnerable, because they're both in the same position vis-à-vis the actual hierarchy. Even Thor and Mo-Mo would fall under this one. But regular old men, they will surprise you and do incredibly cruel things to you without even knowing they're doing it, which is why if you're going to trust them with even a piece of yourself they have to be cordoned off: Kevin here, Eddie there. And if you're Sam or Coop, the power differential is so torqued and fucked up that there's never going to be a way around it. So it's war, all the time.