I agree that the flying back was ridiculous (they seem to have changed it in the most recent build tho) - I was hating that. In terms of reasons though, I think that even an energy weapon would still exert recoil in zero G. We use ion engines to propel ships in space and this is basically just shooting a stream of stripped electrons (energy) away from the entity in the opposite of the direction we want it to go because for every action there is an equal and opposite reaction.-Our weapons don't use ammo. So they must be energy based weapons. Those have zero recoil.
Check it out now though - I think they've listen regarding chilling out the insane recoil effects. Recoil right now seems super tame.