You're right the world has gotten a lot uglier and there are bad people out there. All the more reason to have the ability to defend yourself. Why are you ignoring my reply to you? You have never been a victim before have you?
This is why this topic is such a great topic for debate, there are so many variables, and having been robbed, you would have more of an emotional/passionate view on something like this. I expect you want to hear 1 of 2 things, either to agree with you, ie. arm yourself and let fly, or to say remain unarmed and get robbed/killed? I think if faced with that situation, most would want the "protection".
However, if you have a gun in the house and faced with this scenario, as rare as it may be for the majority of people, I wonder if it would even help? Again, I should stress this is not right or wrong, just food for thought:
a) a responsible gun owner would have their gun locked up, which would make retrieval during a hostile home invasion almost impossible in said circumstance.
b) assuming you didn't lock the gun up (scary as that seems, but that's a whole other topic), do you think most humane people could actually look another person in the face and pull the trigger? Even in defense, don't undermine how difficult this is. Furthermore, does you having a gun now turn what may have been a robbery turn it into a shoot out, Wild West style? Remember, most home invaders want the loot and are not there to commit a senseless murder, but if they are facing someone armed, they will probably not hesitate as much as the other guy. Again, not true in all cases of course, but something to think about.
I hate to sound like an ass, but if you live in a rough neighborhood, do what you can to get out of there, move, give yourself a better chance of avoiding sad situations. Something North Americans have been trying to do for many years. It'll give you a better chance than an arms race in the community.
With or without guns, you cannot eliminate risk, only try and manage it the best way we feel we can.