In 2011, economist Justin Wolfers called student debt forgiveness the "Worst. Idea. Ever." in a Freakonomics post. Why? First, there's the distributional effect.
Source: If Student Loans Might Be Forgiven, Why Not Borrow More? - Foundation for Economic Education
This article explains a number of ways in which student loan forgiveness would be a terrible idea. The fact that it would amount to a regressive tax and encourage more borrowing are at the top of the list.
While there is no doubt that a college education is a great investment for some people, that doesn't mean that student loan forgiveness is a great investment for the average taxpayer. Particularly those that did not go to college or did not borrow money to do so.