Domestic cats have been in the UK for ~2000 years, and wildcats for >~8000 years.

Their only real predators in the UK are cars and dogs, and most British bird species are well acquainted with cats, and on the whole aren’t at high risk. Recommendations say an outdoor cat is a healthy, happy cat.

The RSPB (bird conservation charity) doesn’t find them a major problem here, but do recommend:

1. Neuter them
2. Keep them in at dawn, dusk & night
3. If they ever kill a bird, put a bell or beeper on the collar

Which seems a reasonable set of recommendations.

On the other hand, the USA and Australia don’t have the thousands of years of history of cats as part of the ecosystem, and they have all these wild dog-type-things and snappy reptile things etc, so the cats are in more danger, and the native bird species are at higher risk. Recommendations say an outdoor cat is a bird-murdering machine that’s about to get run over by a giant SUV and then eaten by drop-bears.

My Eastern European neighbours think it’s weird that we let the cats inside at all. They think they should live entirely outside.

So I guess “different countries, different rules”.