>guilt tripped and berated by her wealthy farm-owning (thus probably conservative) mom
>some sort of sensitive thing happened between Jax and Ragatha in the past
>Jax resents Ragatha's kindness because it feels like being taken advantage of
>their fighting over Pomni, and Ragatha clearly being perturbed by Pomni seeming to get closer to Jax

Ragatha is a lesbian. She and Jax were friends initially, and because of her kindness Jax developed a crush on her. When he made a move and got rejected, he felt led on, started lashing out at her, and lost her friendship.

Either that and/or they knew each other in the real world, since he has a weird thing about corn. Maybe worked on her family's farm?