I can agree that humans should not have brought cats and other nonnative animals all over the world. But it is natural that cats are in Europe and North Africa in the first place, given that they have been there "forever". How come there are still small birds and rodents in Europe and North Africa? Cats are hardly more disruptive to those environments than other native beasts of prey. At least some conservationist complaints about cats seem rather simplistic and out of place.
Well, I do have to mention that although of course it's natural for cats to hunt birds and small animals, it's not natural that the cats are there in the first place. Humans brought cats all over the world and they have become a major invasive species. Their toll on native ecosystems is huge and is a big concern for conservationists.