Freespace combat is designed to be fun to play, not very realistic. Capital ships risking themselves by exposing themselves to beam broadsides and bomber oversaturation attacks is even dumber than today's CVBGs doing so.
They could use kinetic weaponry at long range. They could use active missiles and time them to arrive at target at large swarms (this is not unheard of even in 1960s). They could stay as far away as to make single-person ships too prone for countermeasures and AA fire (what's the point of limiting the range of AA fire anyways? You could give it range as long as you like if you can deal with the recoil..). Why would small ships try to get so close to each other that debris from exploding ships could seriously damage the winner of the fight? Whe would bombers use short-range medium-punch tactics when they could just tack engines on both the bomber and warhead? Where are decoys? Where are warhead evasive manouvers? Why does all combat take place in very low-relativity velocities? Why do fighter fly in straight lines? Why don't they tack fighter weapons into turrets, giving them insane fire rate with apparently very little energy cost (think HL-7)? And so on.
Freespace is World War II in space. It's not realistic, because if it were it would be really, really boring and short arcade.
