During the real estate boom, a lot of lenders effectively stopped requiring down payments. One consequence is that, if the value of the house drops, and the buyers want to leave, they can hand the bank the keys and walk away without losing anything. If the price drop exceeds what little principal they've built up, they literally have nothing to lose.
Apparently, there are bankers that feel that people who are doing this are somehow letting the banks down; one from Wachovia complains that some of them "had the capacity to pay, but basically just decided not to."
Well, one thing that gets said of troubled homeowners is that they made a deal, and if it went sour, then maybe they should have thought more about it going in. If that applies to poor zhlubbs who got pressured into a bad snap decision by pushy realtors, then it surely applies to the banks.
Then again, maybe this is just the new American ethos, in which forgiveness is only for big shots. One off-beat thing that's shaping my perspective on this a bit is seeing the reactions to a much-loved local ice cream shop that got into tax trouble, and (making no excuses) is asking for those with a will to extend a little help. Now, mind you, I don't see this personally as a charity thing. I make my charitable donations elsewhere, and I'm giving them a little cash because I've made a cold, hard-hearted, purely self-centered calculation that come summertime, I'll want their ice cream. But if you read the comments on their impromptu blog, it's astonishing how many people there are apparently offended by the idea that people might want to help a friend who's in trouble, even if some of it is their fault...