The store owner did not consent to the robbery, by definition. The bank consented to the contract and agreed that the home would be sufficient collateral for the loan.
Home loans are based on collateral. You borrow money to take ownership of the collateral, and if you pay back the loan, you get to keep it. If you do NOT pay back the loan, the lending institution reclaims ownership of that collateral according to the contract.
This is mutual protection because things can change for the worse as well as for the better in the future.