Aside from starting a gun race with the burglar and fearing losing your life altogether with your possessions, I never follow this reasoning. How is it worse facing without guns a unarmed intruder than facing with a gun a well armed one?
If you're physically weaker than the other person, it's pretty clear how it's worse. Two people with guns is a much more even match than two different-sized people without guns. And that's ignoring the criminals-will-still-have-guns argument.
It improves your odds, but raises the stakes. You should only raise the stakes if you care more about successfully stopping the intruder from taking your stuff, than you do about increasing the risk of death.
At the end of the day we still need to look at the stats (how often do intruders hurt/kill homeowners when unprovoked?), but it still doesn't make too much sense to raise stakes for the sake of survival.
Contrary to what Hollywood would have you believe, the vast, vast majority of home intruders don't want to murder you (it's so rare that these people get special nicknames like "Son of Sam" or "Zodiac Killer"). Most intruders just want your shit so they can sell it off.
Adding a gun into the mix runs counter to simple common sense. The rational response is to have property insurance and stay out of a burglar's way.
This approach is a double win. 1. Nobody dies (yay!) 2. You get brand new stuff paid for by the insurance company!
For better or for worse that argument is facile in countries where guns are already plentiful. No one gets to choose whether their intruder will be armed.
