No. So as long both parties are aware of and freely accept the consequences, no contractual terms that do not violate the law should be considered immoral.
What “implied intent” do you feel is in a mortgage contract? I agree to pay, and if I do not, then you get my home. I agree that implicit in the contract is a good faith effort to attempt to pay. However, it is not a suicide pact.
Example: I have a friend who bought a home in South Florida in 2006 for $265,000. In 2007, the house was worth $296,000 according to the county tax office. Last year, the tax office valued the home at $116,000. He had an interest only loan, so he not only has zero equity, but is currently upside down on his loan to the tune of $149,000.
$150k! That’s enough to buy a whole new house with the difference! That’s enough to put a kid through college and grad school. That’s enough to do an enormous amount of things for a middle class person. So take a credit hit that will stay with you for 10 years. He will be compensated $15k for each of those years. Enough to buy a car per year. Should he decide that it is a point of honor to pay the bank the extra $150k?
You may say that he took the risk, but so did the bank. Why should it fall on his shoulders when the bank, who are experts in the field, should have known the situation better than him?