One reason you might not think it's a big deal is because the genocide is almost complete. They've already killed off 63 species and more in progress: https://abcbirds.org/program/cats-indoors/cats-and-birds/
We could start by requiring all domestic cats to be sterilized, so that they don't breed. Then the cat population would be limited to certified breeders and wild cats.
We could also have the same restrictions on cats as dogs. They should not be allowed to be outside unless they are in leash or in a controlled environment (the latter is hard, as cats can climb over standard fences). I guess fully enclosed "cat parks" would be an option.
You may have a harder time training a cat to wear a leash compared to a dog, but it's possible.
It's strange to me that we think cats need to be outside to satisfy their predator instincts, as if dogs and other animals like to be inside all day while we are at work. If someone doesn't like that thought, they have the option of not owning a cat.
I know that we've come a long way and pets have had humans around them for ages, but to me it still feels like we're doing them harm. I know that nature is even harder, but it's not like pets decided to live that way.
It's also hard to understand why people love one species, but also breed others on an industrial level, so they can eat them more easily.
Probably going to get a few downvotes for this.
We have feral cats in our neighborhood. One of them moved into our house and had a litter in the study. (We kept one, and found homes for the other 3). One of her daughters from an earlier litter moved in and fed the same.
All have been sterilised now obviously, but we stoll get regular visits from a local Tom, likely a brother to the first one. The all get along fine, and he's used to us but basically comes in for food or shelter and doesn't socialise with us like the others do.
I don't think we "own" them. They all come and go as they please. But I'd say 3 of them definitely live here, and tolerate us.
Interestingly none of them seem interested in birds. The occasional mole, otherwise the occasional lizard - mostly for sport.
I'm not negating your ethics at all, but it seems some cats like being part of the family, and others are aloof. They all have distinct personalities.
I've owned cats and dogs. I can let them outside and leave the door open, and they may go outside to explore or play briefly, but they'll want to come inside shortly afterward. Especially my dog - he doesn't even want to be outside by himself, except to relieve himself. He has herding instincts and is uncomfortable being alone outdoors for more than a short time. He would much rather be around people, but if he had to be by himself, then he'd rather be indoors. (Observation: if I were to leave the house, and left the back door open, he'd still spend most of the day inside rather than in the yard.) My cat acts downright frightened being outside.
It's not really possible to discuss what is "natural" here, and I'd recommend being cautious about the naturalistic fallacy [1]: the idea that because something is 'natural' it must be better. It is 'natural' for humans to die of all kinds of diseases, yet we do not wish to, and so we treat ourselves with antibiotics and other medicines. It is 'natural' for children and women to die in childbirth, but we take substantial steps to prevent that, and so on.
In the case of domesticated animals, it's hard to reason about what "natural" even is. The animals have adapted to living with humans; they want to be around humans. They aren't feral, and wouldn't want to live by themselves in the wilderness any more than a human would. They have a choice every time I open the door.
(And yes, if they ran away, I would feel obligated to find them, but that's because I'm responsible for their health and safety, not because they are my prisoners. The point is that they don't even come close to making the choice to do that. It is far more likely that they would simply get lost outside than actually intentionally run away. This has happened once before to my dog, and his emotional reaction upon me finding him demonstrated compellingly that he felt lost and was happy to be found and reunited.)
I might feel conflicted if I ever had a pet that behaved like it wanted to escape from me, but that's never been the case. Even pets that do enjoy to spend time outdoors alone - and I'm happy for them to do that - always want to return to the safety of the home after a time. I would not enjoy having a pet if I thought at all that it felt like a prisoner.
Lastly, I would remark on the fact that these animals were raised from infancy by humans and around humans. They are socialized to be part of the family, just like people are. While it is true that they would have different personalities if they were raised in the wilderness, the same would also be true of a human child. If a human child were abandoned alone in the wilderness and somehow survived, then this human would undoubtedly have great difficulty socializing as an adult, and fitting into a family - yet we would not say that this wild person is somehow better or more natural. We would say that their upbringing was cruel.
Most summers the reserves turn into more of a free dog toilet, and with the vast numbers of dogs going through, it ends up smelling quite bad to.
As something of a response to your proposed solutions, I'm a proponent of TNR and adoption, and teaching people to be better animal caretakers. You make some assumptions about "us" and "we" that doesn't line up with my personal take, so I won't say more.
I mean, you are explicitly talking about ending our symbiotic relationship with the domestic chicken. We certainly would not have 20 billion chickens in the world if we all stopped eating eggs.
...from cat owners.
There's plenty of concern from wildlife-lovers:
https://www.theguardian.com/environment/2022/aug/14/cats-kil...
I watched our neighbour's cat take a bird from a feeder in our garden earlier this month, I was pretty unimpressed :(
Cats are cute, I get that ... I'm just not sure that's enough of an excuse.
Remember that this goes both ways. Birds are probably the deadliest predator for outdoor cats. This is why cats tend to have instinctive acute reaction to big flying objects.
I'm not a cat owner, I like both cats and birds
If something is killing birds, even a lot of birds, but in a place where those birds are abundant and whatever is killing them will just lower lower their equilibrium population a bit rather than set it on a decline or lower it so far that they might die out in the area then there generally isn't a lot of concern over it.
Hence activities in places with species of birds that have low population or are threatened or endangered tend to draw more concern than activities in places where that isn't the case even if the latter kills way more total birds.