There are lots of Corsairs and TBH around, they don't really need the backup of a lot of allies. They also have... A bomber (which Bretonia doesn't currently have), excellent shield busters, decent gunboats (as opposed to the giant heaps that are the Bretonian Gunboats), etc.
If the Hogosha and Gaians get in on it, then you have to allow the Mollys. They are as determined to keep the Corsairs out of Bretonia as the BAF is. Then there's the Junkers who join up to fight against the encroaching Hogosha, the Hessians fighting against the Corsairs (who have to fly through RH space to get to Bretonia)... Eventually it gets to the point where pretty much every faction in that half of Sirius has a 'good reason' to be in the fight.
