Someone breaks into your house with a knife with the intent to cut your throat and steal anything that can be sold quickly.
People have been murdered by burglars many times so you can't bury your head in the sand and pretend that's not an outcome.
In your ideal world, do you prefer that the victims allow the burglar to eliminate them as a witness?
That is assuming a lot of thinking from a scenario that started as:
> I don't know who you are, why you are in my home, and what your intentions may be.
Even assuming what you said, the right to take a life is not a right a citizen should ever have, in any situation.
The right to kill in self defense exists in many countries but I belive in most countries it will result in an investigation and you'll probably have to go to court to convince a judge that you had
1. Reason to fear for your or someone elses life
2. considered (and if possible: tried) other reasonable options.
I think it would be extremely cruel to punish someone for defending themselves or someone else.
Also keep in mind that stopping an attacker without the option of hurting them seriously is way harder than if you are allowed to use any means.
Using deadly force to counter a purely material crime is madness.
Its not the victim's obligation to quiz the home invader on their intentions before they act to protect themselves, their family and/or their property. A person knowingly and foreseeably puts their own life up for forfeit by invading another's home... and for what - a material crime, as you say? (But I hope we all acknowledge that the stakes are often far more serious and irrevocable than having your ipad stolen while you sleep).
The big open secret here is, no government today or in the past has had a monopoly on deadly force (nor will they ever). They only have a monopoly on punishing deadly force via the judicial system.
Deadly force can be legally prohibited and morally justified. It can be legally justified and morally abhorrent.
> I don't know who you are, why you are in my home, and what your intentions may be.
to shooting someone would in most countries be considered a illogical and reckless act.
I'm having a hard time thinking of any scenario where taking someones life is a justified, logical and logically judicial act. Especially in the case you said.