They didn't.
So, why protect the lenders to any greater degree than other loans they make at the same rates.
The net effect and probably the objective of this WH is to kill off the private lenders and let the federal government assume all of the lending responsibility, thereby increasing federal control over our lives even more.
Just because the loans can't be discharged in bankruptcy doesn't mean that borrowers actually make good on the loans. That's why interest rates haven't fallen much. However, the fact that these loans can't be discharged in bankruptcy is why student loan interest rates remain far below credit card rates despite the fact that these types of loans have one key feature in common - neither is backed by physical collateral that can be seized to cover the remaining loan balance.
Student loans are mostly prohibitively expensive at market rate when bankruptcy is allowed.
Look how many students don’t pay up and are generally an expensive hassle to track down. Those rates on guaranteed loans are still way below what they’d be on such an open market.