The decline of songbirds

I am so fed up of some people blaming the decline of songbirds on cats ! In particular some people in the USA are always saying 'Keep your cat in at all times,they are killing all the birds'
What rubbish ! It's just an excuse to justify their distaste of people, especially us in the UK, who let our cats have their freedom.
What about all the pesticides used now on fields, what about all the natural habitat, hedges and trees, taken from birds to make more space for the ever breeding human ? What about weed killer on gardens and less people who bother to feed wild birds any more ? What about all the fumes from more and more vehicles on the roads and the stink of barbeques rising up into the air ?
Cats have been around and free a long long time now but it's only in recent years the number of birds have declined , so how come cats are suddenly blamed ?
Has no one heard of live and let live any more !