Do you understand that banks are supposed to go through a diligent vetting process and not give mortgages to those who are trying to buy out of their budgets? The bottom line is, he who holds the money has the power. The banks are not innocent here.
Nor are the banks that used illegal means to impoverish and enslave these people, or the economy with the huge collapse and millions thrown out of work, or the for profit healthcare system which bankrupts us. How about the inability of working women to earn equal pay for equal work? All of these things enter this picture. It isn't about people not having intelligence or being dishonest. It's about abuse at the hands of the banks, corporations and miserable governance most of which has been perpetrated by the right (including libertarians) in an effort to give those that have more if not all of what there is.