I think what's going on here is that this guy has a narrative he wants to tell about debt, so he'll tie together otherwise uncorrelated bankruptcies to make his case. The fact that he doesn't really make the case isn't surprising. His diatribe in the above linked piece talks about how sovereign debts have gotten "worse" (his word, not mine) since the financial crisis, without mentioning that the borrowing rates are near, at, or even below zero. Not all debts are created equal, and if I'm paying you to hold my money for me, are you even in debt to me? The Detroit thing was just another illustration that the dude is trying to sell ad clicks and not teach anyone anything about how money works.
If tax revenue has fallen, then the same debt carries a heavier burden. The guy's narrative might be extreme, but the solution to debt is inflation and growth. To get there, Central banks print money and lower rates. Rates have been low and money has been printed. If inflation and growth don't kick in...