Frustrated and sad right now

I live with my parents and my younger brother; brother and I are both college students. I have lived independently, but it's expensive right now and I have health problems. I own a dog, and my parents adopted a kitten this winter.

The kitten is fine; but the local songbirds are not. Two weeks ago kitten brought in a nestling Mockingbird. Two days ago the kitten brought in an immature male anna's hummingbird, which was alive and mostly uninjured, and which I managed to release outside again on the advice of the local SPCA's wildlife rehabbers.

I have asked my parents to keep the cat inside, at least until all the nestlings and fledglings are out of the nest, but I've gotten a ton of pushback (and anger!) for suggesting that a cat who's a determined hunter shouldn't be allowed to hunt when his chosen prey are songbirds. I love wild birds - I love birdwatching, and do it regularly - and it kills me that this cat, who is a charming and affectionate housepet, is outside raiding nests at all hours.