I'd also love to know why this site is seemingly infested with Occupy socialists that wannabe libertarians. Greed isn't a crime, so why are you upset with Wall Street or banks? They're in the business of making money, like everyone on this planet, and last I checked they didn't defraud anybody en masse.
Go after your government that induces malinvestment in the secondary mortgage market (loan purchasing, Fannie & Freddie), which then trickles down and induces malinvestment in the primary mortgage market (loan origination). The primary mortgage market would NOT GO BELOW their institution's debt-to-income ratio UNLESS IT WAS A GUARANTEED PAYOUT, and it was. If Fannie and Freddie didn't lower their standards, and buy this junk paper, the loan origination market wouldn't make the loans, plain and simple.