A liberal arts or pure science education is not meant to be a professional degree. It's a way to learn a lot about a particular topic, independently of whether that directly helps your employment chances or not...Historically,...But it had the unfortunate side effect of starting the thought in people's minds that universities are vocational institutions, rather than institutions of higher learning...
The "culture wars" is at play here. Since Uncle Sam is handing out these loans, many tax payers want a good monetary return on their investment (or lowest loss).
Typically Republicans want their tax money going to direct job creation rather than what might be called general enlightenment. They view general enlightenment education as less useful, the job of religion instead of college, and/or "liberal indoctrination". Thus, they are against anything outside of (directly) providing jobs to the loanees.
I'm not trying to pick sides here, but rather convey the conflicting political views that are at play.