Not all the countries mentioned in the article are poverty-stricken . Also the US has many poverty-stricken areas of the country. The point the article was making was it isn't so cut and dry to compare the US to just a select pickings of other countries.
And the article is wrong. The Mises Institute is a conservative biased organization and this report they did wants desperately to have the US stop comparing the itself to all the other developed countries in the world when it comes to murder. Even though we rightfully compare ourselves to all the other developed countries in the world in our other aspects, like education, health, life expectancy, etc. The Mises Institute wants us to make an exception for murder because they are against gun control. It is a cut and dried attempt to bias the numbers on their part.
As for having poverty stricken areas, so do most countries. The point is, ON AVERAGE, the US is one of the wealthiest countries in the world. 56% of our Food Stamp recipients, who are the bottom seventh of the country income wise, drive their car to buy their food. And many of these Food Stamp recipients are too elderly or disabled to drive-so the number of able bodied Food Stamp recipients who have a car to drive is even higher. I'm not saying the car is late model or might not have a few dents here and there, but they are driving, and they are the poorest one seventh of the US population. That's pretty damn wealthy compared to most of the rest of the world. We compare ourselves to the other wealthy, developed countries in the standard of living measurements, I don't see where the Mises Institute gets off deciding to abandon that so they can make the US murder rate not look so bad.