Bombers have bombs. As in plural. And are capable of actually destroying a capital ship, given a dozen or so and enough time. This has one large rocket, and a sixteen-pack of antifighter missiles, and would be going up against a set of capships that aren't the pathetic weak things that are Freespace cruisers, but are actually pound-for-pound its equal or (in the case of the rich factions) better. Think Ares, not Ursa.
Capital ships are more than just two-seaters with lots of guns. Far as I'm concerned, they're anything on a scale roughly from a midsize house to a set of city blocks. In TAC, combative capital vessels are built like a brick ****house with relativistic-slug guns and plasma flamethrowers, anda few measly plasma guns or lasers wouldn't pose a serious threat any more than your grandpappy's shotgun would be a problem for an aircraft carrier. Anything from there on up to large moon size is a cityship or barely mobile space station. Or an actual moon or other celestial body with enough manmade structures to basically qualify as a ship. And even the nonmilitary ones (i.e. basically all of them, there is such a thing as overkill) would be equipped so as to prevent the aforementioned military cruisers and so on from gutting them like a Christmas turkey, and hence would far outclass even a bomber parallel to the Ursa.
This is designed more or less to take out fighter escorts and threaten civilian freighters, which are sized like capships but with a lot less armor and no guns to speak of. It would be terribly unsuccessul in taking on a cityship.