The old saw says that if you owe $10,000, the bank owns you, if you owe $10,000,000, you own the bank. It's always been true, but Republicans by and large are the party of the guy who owns the bank - their leader, as already pointed out multiple times, has gotten out of many many millions in debt through bankruptcy and stiffed untold numbers of contractors and tenants by wielding his excess economic power. They just can't stand it when the script gets flipped and the people who are supposed to be owned by the bank get a little something.
I don't think this has been pointed out in this thread: Student loans are much, much harder (to impossible) to get rid of in bankruptcy than any other kind of debt (google "Brunner test"). Contra, it is easy for a company owned by a billionaire to get into bankruptcy and resolve all its debts. See, e.g. not only Donald Trump but David Tepper's Panthers HQ bankruptcy, just to name one that's been in the news. Rich people are happy to take advantage of the law when a risky business deal goes south. When a poor person makes a mistake in choosing their course of study, or just has bad luck in life, the rich people think it's a horrible sin and an awful moral hazard to let them off the hook in any way.