See title, because it's the same as bailing out the banks, which is the problem. Otherwise bank will just give out more loan and have the student ask for government to bail, and it repeats.
If anything government should make bank outright cancels it (which isn't going to happen) or just make all the loan NO interest. ( more likely )
Using tax dollars not just make some people not want to support it (which is an issue), but also not tackle the actual issue ( stupid high rate and banks)
Again, personal opinion.