The majority of first time buyers bought their homes to be part of the American dream and build equity instead of paying rent. Low interest rates allowed them to do it. They intended to live in those homes and they were not speculating. Most foreclosures were the result of losing a job. Especially for those that traded up.
Walking away from a home that is worth half of what you owe on it is good business. Corporations do things like this all the time. They take the loss and move on. Why is it unethical for the average guy, but not for corporate America?