[specialist]

The alternative to empiricism (science) is rationalism (wish-casting), not pragmatism (least harm).

I often let my dog off-leash. Weighing the risks & rewards, I pragmatically choose to break the law, knowing full well that I'm in the wrong, not some special case. I eat the tickets and social scorn without complaint. My dog has pretty good recall and is super gentle (esp w/ kids). But the big bad govt (and other parents) didn't write the laws with my special pooch in mind.

You're confident your cat doesn't harm birds. Terrific. It's still wrong, in the general case. So take your lumps.

A (huge) point in your favor is that 2/3rd of (domesticated) cats are feral. So keeping cats indoors in order to better protect birds seems quixotic.

In these parts, owners keep their cats indoors to protect them. Recently, my SO's cat escaped her "catio" and was swiftly caught by a coyote. (A neighbor saw it happen. Horrifying.) Maybe your locale doesn't have coyotes.

Edit: Another exception (that I can think of) is farm/barn cats. Pretty much a necessity. Alas, coyotes. And probably hawks.