That particular meme is just mind-boggling. Equating college loans to individuals with the overnight rate to banks? Wut?
Of course her audience of progresssives just ate that shit up, but they A) hate banks B) probably have no idea what the overnight rate actually is C) are no doubt drowning in school debt.
You bring up a very important point. That rate she is quoting is for overnight loans, which have almost no risk. This is not dissimilar to why a 15 year mortgage gets a lower interest rate than a 30 year. There are other factors, but this is one reason.