@strypey I think it's relatively clear: the introduced predators are infringing on the right to life of the native species that can't defend against them, and thus it falls to us (not incidentally whose fault it is the predators are here in the first place) to hold the line on their behalf.
We should certainly take steps to make the deaths of the predators as quick and painless as we can achieve, but I don't think it unethical to do so in the wider service of conservation.
I guess it's a similar argument regarding human non-violence. Like, Vladimir Putin isn't leaving Ukraine just because we ask him nicely. Force, unfortunately, is sometimes necessary.