Did you read the paper? It’s very much not an argument for Peter robbing Paul. Unless you’re saying investing in people’s education is robbery?
It's robbing Peter to pay Paul. Someone with student debt gets relief and greater spending capacity and everyone else just get some more national debt and higher interest rates.
It is all upside for one party and all downside for the other. As the paper states, GDP goes up, but less than the total cost over a 10 year horizon.
Forgiving 1.4 Trillion debt is predicted "Over the 10-year forecast, the policy generates between $861 billion and $1,083 billion in real GDP.
Now GDP doesn't equal federal revenue so you are really looking at adding $1.4T debt for a fraction of $1T in returns.