Why filing for bankruptcy if you do not have any assets to protect? That does not make any sense. You file only when you want to protect your house. Recently, some friends of mine split up - he decided to file for Chapter 7, she kept the house (bought mainly with her family's money) and refused to file for Ch 7, citing bullshit moral reasons (she was not the one who spent to money). Guess what, the creditors did not give a shit who incurred the debt, and put a lien on her house, while he weaseled out.
Another example. A person in a condo association where I have a unit refused to pay maintenance fee, and evaded collection. He was betting that we would not foreclose because there was little equity in the unit. Then we engineered a very clever trick (I am proud to be the chief engineer) in which we persuaded the second mortgage holder (a city housing agency) to forego the second mortgage, which made the foreclosure sale a viable option. That forced the asshole to file for Chapter 13 - which required him to make payment plans, so we won anyway (but he stopped talking to me after that, oh well).
So I find it hard to believe that people who file for bankruptcy usually have no assets to protect. That may be true of some, but that defies the main reason of bankruptcy - asset protection.
The piece you are citing looks suspicious - they claim to have a small sample but they tell nothing about their methodology.
The bottom line: I do not deny that variable rate mortgages may be a good strategy for those who know what they are doing. But I am afraid that many people do not - and there is a lot of deceptive and predatory lending aimed at those who can least afford being ripped off. Perhaps this is a skewed view which I see from Baltimore - I am pretty sure that those who buy $1m condos in Manhattan are more savvy - but the risks are higher than you are trying to convey.
Wojtek