I've also read the estimated cost of this is $300 billion, and doing the math on that and the number of taxpayers, I've calculated that the cost to each taxpayer is about $2k, which is less than the cost of tuition for one person at public colleges (or at least, less than the tuition at a public college near me). And this is to pay for the forgiveness for all student loans for these people that have accrued over decades.
Tiny cost to help stop punishing people for wanting to learn in a society literally built upon knowledge, in my opinion. Especially if it acts as a proof of concept that paves the way for future policies applying to new loans -- which would be much cheaper than this all-at-once batch iteration.
I'm in the group of people who would qualify for this. Do I care personally? Not really, I've spent the last 7 years factoring my loans into my budget and I guess I'm content with the sunk cost fallacy now. But do I care as a member of society? Absolutely. This is a wonderful step in the right direction.
EDIT Correction: the $300 billion figure I read is not, as I first thought, annual. It is an estimate over 10 years. Which means the taxpayer cost is actually more like $208/year, not $2k. Even better!