How do you figure? A forgiven loan is written off; it's not as if the federal government would be paying out the outstanding balance of the forgiven loans, since the creditor is itself.
So, taxpayers. The government raises money from taxes, and loans it to this guy. Instead of this guy paying it back, with interest, it turns into free money. Taxpayers bought this guy an education that is manifestly unproductive. Maybe that's good public policy, but if it is, there needs to be a good public policy argument for it. Not just "free money that didn't cost anybody anything". Which is obviously untrue anyway, so I'm not sure why you went there.
And if it *is* good public policy, let's talk about investments, not loans. We're
investing in this guy's education. His degree will make him more productive. He'll contribute more to society. We will have a measurable payoff, either in dividends he pays back to us as investors, or in productivity that he pays forward into the economy.
Forgiving a debt is essentially saying that the lender ****** up, the arrangement isn't working, and the expected benefits will not be realized. If that's true, then yes, we should consider forgiving the debt. We should also consider letting the lender eat the loss, as an appropriate consequence of their bad investment. But either way, first and foremost, we should consider why and how the arrangement failed, and what steps to take to avoid making similarly bad investments in the future.
If we're going to be giving gifts to people because we think they can't pay back a loan, and won't pay out a return on investment, we should be clear about what we're doing, and why.