Maybe they chose not to because they don't think that, for the majority, it's too much effort to expect from a player?
I'll get flamed, but here goes.
If you're handicapped in some way, and simply don't have the physical ability to do so, that's one thing, but remember, if you have everything on autofire so does everybody else. Then the crying about how hard fighting, and how short the battles are will ensue, and damage will get nerfed. And then the crying about how long a battle takes now because damage got nerfed will start up ... not that I've seen this same thing happen in any game before.
Fighting NPC's is childishly easy as it is. I mean, if you can run out and aggro 3 separate full groups of enemies, and kill them all without dying once (or even coming close), it's too easy. Throw everything on autofire? Then what, just fly around clockwise, taking turns between reinforcing the rear shields and the starboard ... sorry right shields? If they were to implement full autofire, they would have to either cut XP down to 15% of what it is now or triple the hull points on the bots. And did I mention that all of the PvP encounters would be affected similarly? Every person you run up against would be a fool to put anything but disruptor cannons across the board, and just have to worry about positioning. Scratch that, turrets all the way; they can spin like a mother, and you don't even need to keep in a particular direction. That would be a gamebreaker.