You have made a promise to pay a certain amount of money over a certain amount of time under specific terms. That the bank requires collateral in the form of the home itself is irrelevant from a moral standpoint. It seems to me that people are more and more tempted by how easy it is to just not pay things they have undertaken an obligation to pay. I see this particularly with credit cards and mortgages, because the creditors either have little to no recourse, aren't choosing to take the recourse available to them (often due to the costs involved) or, like these foreclosure situations, it takes the creditors so much time to pursue that the debtors don't really care.

Sure, you can complain all you want about the unfair practices of the banks and credit card companies, and convince yourself that you don't owe them anything. But the place for that moral outrage is really before you sign a contract with them; afterwards, you are at the very least morally obligated to meet those terms whether there is any sort of legal enforcement or not.