The executive has the power to compromise disputed debts. It should follow that the executive can forgive debts on a class basis, but Congres created a conflict between the two fairly basic separation of powers principles by granting a partial power the executive already in theory had.
The litigation is mostly junk by parties who don't have standing.
The Standing thing always gets me, but the days seem to be gone where a Posner would muse on Standing for pages in an opinion.
The issue is that these debts are not disputed. Yeah, Trump University, etc., where there is fraud, ok. This ain't it, for the most part.
The bigger issue is that the bankruptcy reform act made it virtually impossible to discharge these debts in bankruptcy.