Lethal force against one criminal stops hundreds or thousands of future crimes by that one criminal.
It also deters other potential criminals.
If guns were lethal 100% of the time, we would have much less crime.
[citation needed] The original article would imply this simply ain't so. This follows the same logic that the death penalty acts as a deterrent when no correlation between states with a death penalty and lower violent crime rates exist (let alone a causal link).
Crimes rates vary significantly between the states, with states with such as Alaska, New Mexico, and Tennessee experiencing much higher crime rates than states such as Maine, New Hampshire, and Vermont.
For reference, Alaska, New Mexico, and Tennessee are not lacking in guns per capita. (New Mexico is in fact 3rd in gun ownership behind Wyoming and D.C.)
Some of the world's lowest crime rates are seen in Switzerland, Denmark, Norway, Japan, and New Zealand. Each of these countries has very effective law enforcement, and Denmark, Norway, and Japan have some of the most restrictive gun laws in the world.
So… more guns clearly does not equate to lower crime either globally or nationally. Unless of course you're trying to sell a book, which gullible folks are quite eager to buy and publicize in order to justify their love of guns over reason.
By all means, share with us what YOU think "everyone" knows.