Well I think everyone knows why domestic cats and even the bigger cats, and every cat in between, love laser pointers (big cats aren't stimulated by them). But for the sake of complete certainty here goes. It is because their brains are hard-wired to respond to the kind of movement laser pointers make: fast and jumpy as the 'prey animal' tries to evade the cat.
|Why do cats love laser pointers? Because they elicit the predator response.|
Laser pointers trigger the predator response which is deep within them. The defect with laser pointers is that they are silent and they can't be caught and killed.
Domestic cats are also very attuned to the sounds that prey animals make, especially mice. They can accurately pinpoint the location of a mouse from the sound the mouse makes.
The fact that cats can't kill laser pointers is bad news because they will eventually become turned off by the device. Perhaps the solution is short bursts.
Are they unfair on the cat? I think they are. They are very effective but limited and I can't really recommend them. The best toys are homemade and fragile enough to be destroyed by a domestic cat.