Eh? You do realise that regardless of whether traders are Samura or Kishiro, they do transfer their cargo and then pay for more to the Kusari corporations, so every trader no matter the allegiance is fueling the Kusari war effort by trading with Kusari. The job of the privateers is to make sure they lose as many customers as possible, hence expect exorbitant amounts requested to be paid whenever pirated by privateers, and/or an itchy trigger finger.
You can be Kusari or Rheinland or Liberty, it makes no difference. You're going to get what's going to you for trading with the enemy:P