Yeah but again I would maybe, MAYBE buy that Ul'dah could have people extradited if they had actually shown the Alliance cooperating in that manner.
Instead they show the exact opposite. Merlwyb states clearly. "Limsa first, then the Alliance." So they're trying to imply that if the Warrior of Light and Alphinaud asked for sanctuary in Lominsan territory, she'd deny them? She'd abandon the WoL and all their influence and achievements, kowtow to Lolorito and allow Limsa to be subordinate to Ul'dan interests?

You know the worst part? Alphinaud says right at the end that you can likely go back to Ul'dah because nobody believes you're guilty and nobody will support any action against you.
So this exile is entirely unnecessary because it's canon that Ul'dah is too lazy and lacks any backing to go after you.