I don't know if anyone said this yet and not to be a Jax apologist but he did mention in that fight with Pomni that everyone blamed him for Kaufmo's or Ribbit's abstraction.
We don't know too much but if you're made a pariah to some bullshit that you might have been tangentially responsible for, it would explain why he's such an antagonist, bullying ass.
It may have been his fault totally, but I doubt it since the timelines don't seem to match up. It could be he's being blamed for just Ribbit's abstraction by the others as well; maybe some form of revenge for his antics. It would explain why he didn't get to know other people cause he believes that no one cares for him (Ragatha said she tried) but I don't know just throwing more theories out there.