1) It will be difficult to locate the borrowers because it's been 3 freaking years and people move, etc.
2) The borrowers have gotten used to not making these payments. It will be a hardship for almost all of them when they are forced to start again. You'll get hundreds of Huffpost, NYT, and WAPO articles about poor communications majors not realizing they had to repay this. In the meantime, their circumstances changed because they adopted ten Dreamer kids from Guatemala, etc.
3) It is completely unjustified by the circumstances of Covid right now. Joe "The Pandemic is Over!" Biden.
4) We need the money.