Arcachon didn't just fight a war with Arcaea -- they insulted Arcaeans every chance they got. They made it as difficult as possible for Arcaea to conquer the Dark Isle even well after it became clear that they had no hope of winning. Their mission was to make life for King Velax as unpleasant as possible. So it is no surprise to me that three quarters of what anybody thinks about Ohnar West is made up of leftover grudges against Arcachon nobles.
Never gets old, does it. The Arcachonians refused to roll over and die, when another realm decided to take all their cookies, despite having assured them otherwise. Makes me wonder which nobles really ought to be holding grudges.