The best bathroom graffiti I ever saw was written on a university bathroom toilet paper dispenser. It said, "Philosophy Degrees: Take One."
Now, let me preface this rant by saying I'm an English major and damned proud of it.
As far as why people smack-talk liberal arts degrees, I think it's because:
1) You can BS your way through a liberal arts degree. It's much harder to BS your way through a hard science, with the math and all.
2) Some people who pursue liberal arts degrees give liberal arts a bad name because they manage to be pompous AND unintelligent, all at the same time!
3) People confuse college with trade schools. A liberal arts degree doesn't teach you a specific task for a specific job.
The real problem is #3. College does not teach you how to be something, e.g. how to be a writer, how to be a psychologist, how to be a lawyer, how to be an engineer. College teaches you how to think. How to communicate. How to be independent. How to set and pursue both long-term and short-term goals. How to network. How to work in a team or group. How to succeed within a system. How to play by the rules. How to bend the rules.
Anything else you may learn at college is great! Good for you. But that doesn't change the fact that my dad studied criminology and ended up in sales, or that my boyfriend's dad studied psychology and ended up in hedge funds and financing. I studied English, and even though I've done my fair share of professional proofreading, writing and editing, I'm in the web industry now. In fact, my coworker and I were just talking about how the vocalist/cofounder of the band Bad Religion has a PhD in evolutionary paleontology from Cornell. By the way, my coworker has an MFA in creative writing and is now a graphic designer.
The sad truth is that college does not teach you job skills or prepare you for the workforce. It's purely a pursuit of personal growth. This is a wonderful thing, but there will always be the pragmatic follow-up question: Why pay $X thousands of dollars for "personal growth" if you end up a highly-educated barista at Starbucks?
To which I counter, where are your priorities?! A skill set is static; personal growth has infinite return.
And at least you got to immerse yourself something you were truly passionate about, instead of buying into the "college = trade school" mentality and studying something you didn't really like because you thought it would be profitable. The age that most people do college is the perfect opportunity to dive into something fun before you start the long process of specializing (and subsequently limiting) yourself through career, family, etc.
This also explains why there are plenty of mega billionaires who were dropouts, flunkees or worse. College is not necessary to be successful. But it can help -- and it's darn fun.