There are a few parts to it.
Firstly, as I've posted previously, they're worthless against intruders. The gun and ammo must be stored in separate locked containers, so you'd be dead before you opened them both.
Okay, but that's not addressing the argument. That's saying NZ adds an extra layer of regulation to make the original argument impractical. Kind of like saying freedom of speech isn't valid because the law says you can't speak publicly?
The flip side of the coin is that home invasions are incredibly rare, so there's no need to have deadly force available.
Ok, "we trust our criminals to be nice" is a really strange justification.
NZ has a bit of an issue with beating, raping, and generally abusing it's women, yes? To an American ear, it would be a valid argument for a woman to say she wants to be, you know, not raped quite so often, and would like a last-ditch means to defend herself from a more powerful attacker when in her home.
Finally, the criminals are highly unlikely to be armed, so you'd end up facing manslaughter charges if you kill one.
Ok, and I think if you shoot someone, you should stand trial to assure it was justified, no matter what the laws are or how justified it would seem at first glance. Again, does a woman facing a much more powerful rapist have to box him first, Marquis of Queensbury rules?
I can see it's quite hard for Americans to parse all that, but long history has shown very few examples where a Glock in the bedside cabinet would have saved a life. I certainly can't think of a single instance where it would've been useful.
Have you spoken to any of your raped and beaten women about that?
And for clarity: I'm fully on board with tighter buying/owning regulations and basically no-carry in public. But in the privacy of your home, it seems to me that the most basic human right you can conceivably have is to... stay alive when minding your business on your property. So what I don't get is the State saying "nah, you don't have that right. You can chase a rapist around with maybe a frying pan, but otherwise just lay back and think of England". That's some cold-blooded ◊◊◊◊, man.