The counties are given shades of blue with darker shades meaning more economic distress. According to the label (Newark), the 10 red dots are the top 10 most distressed large cities in the U.S. It appears that almost all of these cities are in regions of light blue shade. That's the puzzle.
A separate issue with this map is that it presents a static image of distress. The first paragraph of the article states: "As the most prosperous communities
in the United States have gotten richer since the end of the Great Recession in 2009, economic conditions in many distressed areas have deteriorated even further." It would be great if we can see a before and after 2009 comparison.