I have a cat. I have always had cats in my life. I love cats. I consider myself a "cat person" (who also loves dogs). But you really are being obtuse here. Even in places where cats are not a threat to literally entire species (as they are in much of the world), they can cause massive, irreversible destruction to the local wildlife. That is a fact.

The argument that it's cruel to keep cats indoors doesn't resonate with me either. Outdoor cats are far more likely to be seriously injured or killed by any number of things that are found only outside. From diseases to predators to sadistic humans, with the big obvious factor being cars. But a well-cared for indoor cat is a safe cat. I'm not going to look it up right now, but it's something like the average lifespan of an outdoor cat is only 3-4 years whereas indoor cats it's like 16-18. In my experience (and I've known a lot of cats, both indoor and outdoor) most that are raised indoors are perfectly happy to remain that way so long as they are given the things they need. That includes exercise and mental, emotional, and social stimulation. If you provide for them, there aren't many things they desire that they can get outdoor that can't also be given to them indoors. It is much more cruel to have a cat that you let outside but mostly ignore except to feed them, than it is to have an indoor-only cat that you make time for every day to play with, give affection, or otherwise engage. There are also plenty of compromises if you're a human that's privileged enough to be able to provide them, like outdoor enclosures.

Finally, this thing about calling the "cats should be kept indoors" argument an American position is just crude and wrong. The American way is more along the lines of "lol, I'm going to do what I want because I feel like it, I don't give a shit about all the evidence that what I want is harmful to others." In other words, "I don't care about the local bird, rodent, reptile, and native predator populations, I'm going to do what I want with MY cat" seems to be a hell of a lot more of an Americanism than @Egon@hexbear.net explaining to you why outdoor cats are a detriment to wildlife all over the world. When it's also taken into account that it's typically islands that have suffered the worst consequences of cats as an invasive species, islands that are also victims of US imperialism, saying that cats should be kept indoors is an American moral imposition is straight up offensive. At best, it's adding insult to injury.