If this phenomena is true then there could be many reasons why abduction occurs - experiments, curiosity, something in our bodies they want/need? The list could go on and on. Going with some evidence it would seem to suggest that animals are also on the hit list. Animal mutilations have been around for many years now and still cause a lot of scratching of heads - personally I feel sorry for the poor animals as they don't seem to have had a good time of it with the so-called 'aliens'. Now whether it is aliens or not, these poor creatures have died and that is a worry! Which begs the question:
...if 'they' are so advanced, why do they need to 'abduct' at all.? Why do they need to kill animals? Haven't they got the technology to sort their own problems out - if that is the reason for snatching people/animals? Secondly their methods would seem to be nothing short of barbaric. 'Abductees' have reported feeling immense pain during and after an abduction scenario - at least with our medics we get anasthesia etc.. Perhaps they are a species that does not recognise pain/fear or perhaps they don't care? Either way they seem to be backwards to me, not superior. How they abduct - there seems to be a method which implies some form of hypnosis/paralysis that makes people co-operate.
At the end of the day whether these scenarios are actually happening or there is some other explanation other than aliens is still up for debate.