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.
Just think about it.
Answer:
Then why did the Corse assist the Council in the war?
And why do they have them as enemies on the rep chart?
The Royal Crown (navy) is incorruptible, therefor impossible to get past, they are an obstacle, no matter how you twist and turn it.