> Why must an intruder, who may be there just to steal something and not harm others, immediately have to pay for their actions with their life?

The loss of property, and the violation of one's home and sense of security are real harms. But the point is not to make the violator pay, so much as it is to merely prevent an injustice.

And many (I believe most) defensive gun uses involve merely brandishing the weapon. Most people do not relish the thought of taking another's life.

> Do gun owners truly believe that they can band together and stop the entirety of the United States military anymore? The same people who are large proponents of the 2nd Amendment also seem to encourage a massive defense budget which seems backwards to me.

It makes more sense when you realize that there is significant overlap between "gun owners" and "past or present military service".