Money went from the government's big pool of money to a thing the government decided was a good idea. That's literally how all government spending works. We can collectively decide through our system of democracy that education is a good thing and that the single largest source of unsecured debt is probably worth addressing and not have the argument of "but it doesn't affect that group of people." If you want to get incensed about uneven distribution of wealth, get angry that the tax rate for the highest earners is the lowest it's ever been (and no, debt forgiveness doesn't benefit them).
It's also naive to think that relieving debt from the middle class won't benefit the economy in some way. America's middle class goes to college. It's hard to argue that consumers having more money to spend won't drive economic growth.