yes, I feel there is a moral obligation to repay a loan
if a situation arises where repayment becomes difficult, I also believe their is a moral obligation to attempt to re-visit the terms of the loans with the lender( and i feel the lender should have an obligation to entertain revisiting the terms)
and I do not believe there is a substantial difference between borrowing from a bank or a single person in regards to a persons moral obligation to repay his loan.... either you find repaying your loans to be moral obligation, or you do not...who or what the lender is rather irrelevant to this determination.
that all said... **** happens... sometimes a person is completely and utterly incapable of following through with their moral obligation through no fault of their own.
these folks should have a mechanism to find remedy.