Piketty and others have covered this. Debt is primarily a political obligation - in the sense that it's a reified power imbalance in which one person with power "lends" it to another in the hope of making a bet that increases the status and influence of the lender.
It may or may not increase the status of the borrower at the same time. As long as the lender's status and standing are increased, either outcome is acceptable.
But if the status of the borrower increases while the status of the lender is decreased - because of a "default", or some other outcome that damages the lender - the transaction is considered morally offensive.
Banks are simply professional lenders. If the transaction were purely numeric and not political they'd be peripheral to the economy instead of central to it.
It may or may not increase the status of the borrower at the same time. As long as the lender's status and standing are increased, either outcome is acceptable.
But if the status of the borrower increases while the status of the lender is decreased - because of a "default", or some other outcome that damages the lender - the transaction is considered morally offensive.
Banks are simply professional lenders. If the transaction were purely numeric and not political they'd be peripheral to the economy instead of central to it.