To me, sarcasm is a form of a riddle, albeit one highly dependent on the trust and relationship between the two or more parties involved. A sarcastic statement does not always have to convey a "belittling" or "malicious" overtone, but can be much closer to a maxim, a form of wordplay, a metaphor, or an allegory. Or, in the case of the following Futurama quote, sarcasm can be a container for one of the above literary devices:

Professor Farnsworth: Is it true that stem cells may fight the aging process?

GeneWorks receptionist: Well yes. In the same way an infant may fight Muhammad Ali.

I like how the article points out that the over-arching caveat to the benefits of scarcasm involve the 'human capital' of trust. That reminds me of why my friends and I would use sarcasm with each other as games of wit, and why, on occasion, I'd cringe when one of my friends would be sarcastic, sometimes in a not-very-nice way, to a stranger who was simply trying to do their job. Or, in other words, sarcasm is a very powerful weapon in the "put down" game, and a large swath of the population isn't really mentally equipped or practiced in the contest, so it's a belitting thing...but when sarcasm ace meets sarcasm ace, holy cow it can be some funny material.