Both Kusari, Enclave, and everyone else can always choose to do a multitude of different things using a multitude of different justifications.
Kusari could have chosen to promise to re-instate the King as just ruler in exchange for the Enclave's support, and sell their invasion of Gallia as a liberation of Gallia from an illegitimate government.
They could theoretically have done that, if it had helped balance out numbers in pvp. They didnt "have to" do anything of what they did.