The blindness of cat lovers...
Good gravy! Cat lovers think their little moggies can do NO wrong! To listen to the cat lovers, it's perfectly fine to replace wildlife with hordes of stray cats. What's going to keep your trees and gardens pest-free when all the songbirds are dead? Those birds eat lots of bugs you know.
There's good (non-greenie-whacko) research documenting the correlation between stray cats and loss of wildlife in urban-suburban areas. There's also good documentation of how trees without birds are less healthy and grow less (as much as 60% less in a year).
Dogs aren't allowed to roam about killing at will, there's no good reason to let cats do it. As far as "following instinct to kill things", apply that argument to dogs and see how bogus it is. We routinely stop pets and livestock from acting on their instincts, for their good and ours.
Hey cat lovers, do you make excuses for your delinquent children too?