I partially agree with killing of ferals to protect native wildlife - though the cat lover in me is against it, I have a general no go opinion on invasive species, especially when they are as detrimental to wildlife as cats are.
I must be one of the few people in the world who has never actually (knowingly) seen a feral cat.
As for my own cat - indoors only, or allowed in the garden for company. No way am I going to allow the death of native species as sport for my spoilt - enough - as - it - is monster.