We would do it if we found an alien civilization with lesser technological abilities than we possess. We regularly scoop up lifeforms from our air, oceans, trees and all habitats for study and only sometimes do we treat them well. We freeze them, dissect them, breed them, and euthanize them. One of the funnier consistencies is the reports of cows being mutilated as being related to UFO sightings. Let’s just take this on its face. If it were true, it could be nothing more than aliens loving the taste of bovine colon similar to how some humans like shark-fin soup. Maybe a particular bacteria lives in the cow’s intestinal tract and aliens just love it. It could be that simple. If they are abducting humans they either want them to study, to eat, to recruit as agents, to establish relations with, or as playthings for their children for all we know. But if they’re doing it, they have a reason or several.