I think a lot of the problems are self inflicted
Well, yes ultimately. In that each person makes their own decisions with their money. But that's not a particularly insightful view into why people make the choices they do. Many people find themselves underwater. Sure, it's because they are spending more than they take in. Most don't take steps to fix it. Why?
I think as an outsider without these issues, it's easy to look in and say "Well duh, have some self discipline and spend less money." "You're fat? Have some self discipline and eat less calories, obviously." But, there are many factors that lead to people having made bad decisions, and continuing to do so in the future. If we want to understand the choices they make, we need to dig a little deeper.
The article suggests in part that even as the middle class shrinks away, people in it have much of their identity tied to being middle class and accepting that your socioeconomic status is falling is very shameful and emotionally tumultuous. Because of that, folks attempt to continue to live the perceived middle class lifestyle, even to their own financial ruin. Financial ruin is less objectionable than accepting and admitting that despite a college education and a good career, they do not have the same standard of living that the same would have bought your parents. To them, it feels like a personal failing, not a symptom of the economic realities they live within.