It takes a long time to kill a decent Battleship, even the Mako which is bigger and less agile than the Osiris, which you used in one of your comparisons.
The bomber powerplants were lowered. They cannot sustain indefinite fire, not even with three guns.
If a VHF or bomber is holding down the trigger long enough to empty their power, 'UR DOIN' EET WRONG!'.
Bombers also die to one SNAC and are significantly easier to hit with one. Mini Razors also make quick work of them, and are far easier to hit with than the SNAC. I guess if you can't take them out with the MR, you don't have the right to whine about the SNAC.
