Because it's not penalizing those that paid theirs off, and it's not a "reward" for those that are currently suffering from crippling debt. To frame the policy as such is to ignore the fundamental economics that underlie it. RJ put it relatively simply above re: Wake Forest: tuition used to be 30% of average per capita income, now it's over 130% of average per capita income (using his numbers, I don't know Wake well). Public schools aren't much better. In 1970, public universities cost around 20% of average per capita income, now it's well over 50% and only increasing. So to start, anyone who has entered college in the last 10-15 years got screwed and the kids who are entering college now are even more screwed.
In addition to college costs skyrocketing, it's never been harder to find employment without at least a 4-year degree. I am in the process of applying for jobs (pending May graduation) and my entry level salary range is around $40,000 on average. But, every single job I've applied for has at a minimum required a 4-year degree plus at least 2 years experience in the field, and most of the jobs have "preferred" qualifications of a post-graduate degree. And paid internships are increasingly rare and most likely only available for a very privileged few, so most college students are forced to work as unpaid labor until they graduate to meet the work experience requirements and then hope that those hours put in for free turn into an opportunity somewhere.
So college costs are huge, decent paying jobs are mostly unavailable to anyone who doesn't have at least a bachelor's degree, and it's nigh impossible to find an internship to gain experience that will pay you for your work. So how do you pay for all this? Student loans. And what increases as college costs increase and it's difficult to find any work experience that also pays? Student loans. Giving relief to Gen X and millennials will likely boost the economy as literal billions of dollars become available for millions of Americans who otherwise would be paying off interest for the next 20 years. And it will allow Gen Z kids and the next generation to have peace of mind that they are not going to be totally fucked in 5-10 years because college ruins them financially for the next 3 decades.
