Of course, I can see how real estate people and residential mortgage people, as quoted in the original post, would decry mailing the keys back to the bank. What would happen to their business if this became common? Nothing good, I am sure.
But I work in healthcare where I see people default on their bills all the darn time. My employer is one of the largest providers of charity healthcare on the West Coast. We can't very well repossess their surgery or stuff the baby back up the pipe. What should we do to collect on the debt, especially when they refuse to pay? In this scenario, at least there is a house to repossess.
I just don't see where residential mortgage defaults should engender so much ire over and above defaulting on any kind of debt. And especially since defaulting on business mortgages is a common business practice in the commercial real estate arena. From what I read in the business press, we can likely expect a tidal wave of commercial loan defaults in the next several months.
Carrying any sort of debt carries an explicit or implicit commitment to pay it back, be it commercial lending, healthcare, housing, car, student loans or anything. If you default, you should be held accountable, be you an individual or corporation.