You (and NoblesseChevaleresque) have a fundamental misunderstanding of the existing mechanic, and how it works. In short, you demonstrate that you have no idea how the system works at all. I suggest that instead of critiquing something you don't understand, and thus have no basis from which to critique it, you learn how it works. Once you understand that, then you can go about suggesting ways to improve it.
As I understand it, the peasants of a region do not like it when their realm wars against another realm which they like. Feel free to correct this understanding if it's wrong. This can lead to situations as described in the opening post, where regions are suddenly penalised at the onset of a war, regardless of whether the war has any sort of persistence beyond it's declaration. Of course, this can lead to game play abuse as well as strain verisimilitude, as I explained before.
