It's no different than airline bailouts... Hey, let's make retarded investment/business decisions in a market that is critical to the welfare of the country. We'll make some bucks, and the govt will bail us out when the bubble we've created bursts.
Just like everyone seems surprised that airlines go under when they sell airline tickets below cost, why is anyone surprised that lenders need a bailout when they give the same low cost loans to both high and low risk borrowers?