Ah, I see. I thought you meant fighters were "small manned spacecraft".
Manned is part of it, but I personally wouldn't classify a dedicated kamikaze craft as a fighter. Nor would I employ such a thing, unless the situation was truly desperate.
Still, I see no (conceptual) problems with the suicide fighter approach. They're going to be cheaper than a ship, so mutual suicide is perfectly fine. XD
My point was that if the railguns are powerful, then there is a chance that your ships could avoid suicide. We'll have to see how it works when (or if) Steve gets us NA.