Well, there were cases of outright fraud, where the mortgage that was signed, was not the mortgage that was recorded. That kind of crude fraud was certainly not the cause of most of our mortgage problems. The trouble wasn't simply a lack of clarity in the terms of the loan, it was the terrible, self-serving advice peddled, by the brokers, real-estate agents, developers, home improvement networks etc. "Wait, I'm pretty sure I wouldn't be able to afford the payments on the loan after the rates reset." "Don't worry! You'll be out of this house, and on to your next house well before the rates reset. Real estate only goes up! This is an investment, you'll make a handsome profit, just by holding on to the house for two years." Doubtless many were as naive and clueless as the mortgagees, but may other knew better and were simply being predatory.
This ties into the article under discussion. The author relates a story about really want to move out of the back room and on to the trading floor. A friend who is a trader, asks him if he can completely dedicate himself to taking the money of people stupider then him.