If you want to get angry about bird declines then look at what we humans have done to the natural habitat of the UK. Your support is great but shooting an animal is not and illegal. You’d think if anyone would be anti-cat it would the RSPB but they aren’t:
Despite the large numbers of birds killed, there is no scientific evidence that predation by cats in gardens is having any impact on bird populations UK-wide. This may be surprising, but many millions of birds die naturally every year, mainly through starvation, disease, or other forms of predation. There is evidence that cats tend to take weak or sickly birds.
It is likely that most of the birds killed by cats would have died anyway from other causes before the next breeding season
We also know that of the millions of baby birds hatched each year, most will die before they reach breeding age. This is also quite natural, and each pair needs only to rear two young that survive to breeding age to replace themselves and maintain the population.
It is likely that most of the birds killed by cats would have died anyway from other causes before the next breeding season, so cats are unlikely to have a major impact on populations.