I had actually forgotten that was one of the reasons Sorraine declared the war to begin with.
Because it wasn't. Mathilda mentioned it but this was an offense against Cathay, not Sorraine, and Mathilda also made it abundantly clear that her reason for going to war was because Ohnar West didn't deserve to exist and she was going to see to it that it ceased existing. I think at one point she even said that it didn't matter what they did to the one noble that sold food to Kindara, she'd go to war anyway.
OW had no legitimate casus bellus. They wanted a war of conquest. Nothing wrong with that, particularly as they nearly got away with it.
