And I wrote as much. "However, it is the responsibility of outliers in any group to take remedial action if the group rejects the appeal." I'm unsure how to be more plain.
Remedial action is not limited to capitulation or exit, though, else you've justified bullying as something you can ask to have stop, but if they bullies say no, it's now your problem.
No, I've set up a situation where one person is affected by/affecting a group and attempts to reach compromise have failed. Without compromise there are two choices for the disaffected: change or leave.
I reject this simplified dichotomy, as it is based on a specific outcome goal, namely the end of conflict. But rarely does capitulation actually result in a cessation of conflict -- generally it leads to passive aggressive behavior and the transference of the conflict to other areas.
If the initial attempt at compromise fails, it could be for a number of reasons -- your position is unreasonable, their position is unreasonable, or, the far more likely, one or both sides isn't representing the actual causes of the conflict. If you fail to reach a compromise, quitting or quitting is a poor resolution mechanic if you want to actually resolve anything. Instead, direct addressing of underlying reasons and feelings is a more appropriate step, especially in situations as fraught as this one.
Personally, I still feel that the OP is being bullied. This needs to be called out and discussed (since the game is online, this is at least physically safe) or the OP needs to absent himself immediately. On this latter point we agree, but not because it's how you resolve conflicts but because you should never continue to submit yourself to abuse. Abuse being a different animal than conflicting points of view in game.
What part of "... I'm addressing the pathological case." left you in doubt?
I was uncertain if you were using that word as intended -- no offense meant, but I don't know your posting style well and it is the internet; assuming vocabulary skills isn't always warranted. So I hedge in your favor by being explicit. Glad you can confirm.
However, that said, I would strongly hesitate to diagnose pathological behavior from the details in the OP. And, if your argument is only for the pathological case, which would hopefully be far more obvious and verging into abuse rather than disagreement, what's your advice for the OP?
Because at no point is it incumbent on the group to honour choices they didn't have a hand in -- choosing Paladin as a class, for example. Should the group honour it? Yes! Must the group honour it? No!
Two things. Firstly, I specifically called out that the group had already acknowledged and approved the choice of class and oath prior to the events in my example. Perhaps you overlooked that. Second, if the group allows your paladin to start play, they've tacitly agreed to the class. If they allow your oath into play, they've tacitly agreed to the oath. If they have no objection to your play of that class and oath up until the conflict, they've tacitly agreed to your play. Complaining that you don't like the class, the oath, and the play only at the point of conflict is a failure of the group to honor the social contract of the game -- the group is now at fault, not the player. The time to complain is beforehand.
If something unforeseen emerges, as it can do, then that's a discussion that needs to be had frankly and openly with the whole group, yes. However, the paladin not lying for your convenience certainly is not this case, and, as a group, you've already approved this play prior to the events unfolding. The fault is yours. If you then insist that the player alter their character because you've decided to retroactively remove your permission, the breach of social contract is on you, not the paladin's player. If the group agrees with you, and threatens the character with violence, that's essentially threatening the player with emotional violence and is a bullying tactic. Bullying does not go well with capitulation.
In most group environments, one might expect that qualms about adding a with specific and understood principles would be raised early, but perhaps the group is used to winking at those requirements? Even if the group expects the requirements to be enforced and intends to continue their murder-hobo ways, they have no obligation to alter their behaviour to protect you from your choices. It would be appropriate if the group gave you a warning prior to bringing that character in that it could be a problem, but failing to do so doesn't put them in the wrong. When faced with the stark choice disappoint your mates or disappoint your deity, what do you do? What consequences flow from that decision? That's one of the risks the player assumes by playing a character with unbending principles.
This is heavy on blame the victim.