That's a good point, the wider beam at that distance creates a larger footprint within which a target can be held.
The biggest cause I can see for the "superhuman" accuracy that the idiots pointing at aircraft can achieve is like the difference between rifles and pistols. If you take combustion efficiency and velocity out of the argument, from a mechanical rest, with barrels of the same quality, and consistent ammunition, a barrel that is 6" long will be just as accurate as one that is 36" long. However, when placed in the hands of a real user, the rifle is more accurate than a pistol at a given distance every time for two reasons, the much longer sightline between the front and rear sights, and that you can achieve a three point brace between both hands and the shoulder because a rifle has a stock.
With a green laser, the sightline can be miles long, and unlike a bullet where you have one instant to choose in which to release it, the "user" (i.e. plane dotting idiot) has comparably infinite time to adjust as he can just keep watching the beam.
You can also greatly increase how steady a hold you have on the pointer by using three muscle groups in opposition, just like a riflle's two-handed hold against a shoulder stock, is steadier than a one or two handed hold with a pistol. You can experiment with this for yourself inside your home by watching the dot as you use different holds. Try it one handed, then two handed, then with two hands making a double fist holding the pointer and your fists against the side of your jaw using your neck muscles to help hold your hands steady. Each time gets you a net increase in stability of the dot on whatever you're pointing at.
So I don't think it's at all extrordinary that people are hitting the aircraft they're aiming at, or that air crews are seeing the beams. I just think that the brightness levels reported are inflated hyperbole, as they go through each re-telling, from pilot to FAA to the press. No real conspiracy there, just human nature