I believe that his thinking is justified. Aotearoa has many rare and unique birds that developed in an environment where they had no natural predators. That means that many of them are completely incapable of dealing with predators. There are also many types of flightless birds in Aotearoa too. Aotearoa also has many reptiles (though no snakes)
When i was a child living in Aotearoa I had the great fortune of being taken to an island bird sancutary. They had managed to keep all introduced predators (that includes rats, mice, foxes and possums) off the island and the range of bird types living there was incredible.
I think that if people want to keep cats (in general and not just i countries where they are an introduced species) they should be more responsible, especially not allowing them to breed indiscriminately.
Don't get me wrong, I LOVE cats. But, when you consider that every single one of my cats was a stray that had been abandoned to die when a kitten well...