I never said cats in general, I specifically said owned (as in regularly fed, have a consistent home base with incentive to stick close, neutered so as not to roam) cats. Feral cats, semi-feral cats... no argument there. I wouldn't be opposed to them being exterminated, and I'm not at all opposed to people culling them (though I do really like cats and am saddened by it). And I don't think it's fair to include island ecology in this, because island ecosystems are often unique, extra fragile and without native predators.
I skimmed a couple of the articles you left (and I mean really skimmed, I should go back and re-read the better ones):
Of course outdoor (pet) cats kill things. But what are they killing? Native species, introduced species? What are the population trends of those native species? I used IUCN to look up the species of birds I can remember us getting around our place:
American Robin—least concern, population increasing
American Goldfinch—least concern, population increasing
House Finch—least concern, population increasing
Black-Capped Chickadee—least concern, population increasing
Fox Sparrow—least concern, population stable
Dark-Eyed Junco—least concern, population stable
Spotted Towhee—least concern, population stable
House Sparrow—least concern, population decreasing (**introduced species)
Song Sparrow—least concern, population stable
None of them seem to be in trouble (though I'm sure I missed some). As far as mammals go, most of our small mammals are introduced anyways (grey squirrels, house mice, Norwegian rats)... otherwise there are some species of vole, which I'm guessing aren't in any sort of trouble. My guess is that the majority of wildlife you find in developed areas has adapted to living with people and isn't in any trouble (I'm sure there are exceptions).
One of your articles says:
So it may be 1/3 of birds killed by cats are invasive competition for native bird species.
Other things to consider: what is the health of the animals they are killing? Are these species impacted by density dependent factors (e.g. do only xx% of them survive the winter due to competition over food; do only xx% win appropriate breeding sites )? To what extent have has cat predation replaced that by native predators whose populations have been reduced by human activity?
That said, in some areas I'm sure pet cats do have a significant impact on a population (maybe one of the few nesting sites for an endangered species), and yes they should be kept out of those areas, pets or not.