While Qashqai may be arguing from a Brigand point of view, you would do well to consider what he is saying. The Unione Corse is, first and foremost, composed of businessmen. Dirty businessmen. They don't want to free Gallia from the "oppression" of the Crown or advance the political agenda of reuniting Gallia with the other Houses. They want cash. Cold. Hard. Credits.
Realistically, the course you would have many members of the Corse angry because you are hurting them where it hurts most... yes, the wallet. Hostile to the Gallic Corporations but not the Gallic Royal Police? You could skim money off all of those organizations. Welcoming other criminals into Gallia? Competition. Cardimine? That's money that could be going to the Corse that is instead going to the Outcasts.
I don't mean to bash you here, I'm just giving you a different perspective. The Corse are one of the most interesting factions in the game. They're also one of the only criminal organizations to actually agree with the Crown that the isolation is a good thing.
