My argument is you’re spending way too much energy thinking about outdoor cats, which are irrelevant to the larger argument of harm to the environment.
It’s a distraction from the problem that humans themselves pose to the environment…you’d get a lot more bang for your buck and the cat problem would take care of itself it if you were less materialistic, for example.
If you think you’re doing a goddamn thing by keeping your cat indoors, while at the same time running on the hamster wheel on consumerism…I have news for you.