It may very well be that a person's economic and social situation contributes to their decision to commit a robbery (or other crime), but to say that also sort of makes it seem like the decision to commit the crime wasn't entirely their fault. And that seems a little silly to me.

I agree with you in the sense that there are problems that we can address to make crime less appealing to those who might resort to it as a means of improving their quality of life. And no, more firearms doesn't garuntee a thing. But the simple fact is that you can't expect anyone but the perpetrator of the crime to take responsibility for it. Poverty exists in every type of economic system in existence. There is a fine line between saying, "Screw the poor, their problems are their problems," and, "The actions this person took are a result of our (the rest of society) actions," and I'm trying really hard to walk it.

Tl;dr: It isn't anyone's fault that others commit crimes, but there are certainly things the rest of the country can do to help.