True, you may not be able to fly through the Bug capships like you could the Vesuvius, but you didn't need to fly through Ella and Seether sure as hell didn't need to fly through the Amadeus!
Confed (and any other major power) would have course have used any weapon to get the job done, never mind about the morality of humankind. Look at the napalm campaign in the Vietnam war, and the only reason the Yanks didn't nuke Vietnam is because they didn't want China or the USSR to launch a nuclear counterattack! Ah, the lack of American balls which resulted in so much death and suffering.
I myself always wondered about the absence of the Flash Pack, I mean, even if they were useless against the Bugs, Confed would have still HAD them, and tried them out on the Bugs. However, since Casey's lot have first contact (apart from the Deverueax), we can only assume that either (like the Dragon) they're costing too much to manufacture on a mass scale, or that armour technology in Confed, let alone other species, has surpassed it's penetration. True, you could still fry a few Cats with it, but what would be the point?........