I don't think so. But this stuff is always in flux. I see irony as constructive - it intends to produce something. In the case of the author, writing from an ironic perspective was the best way to describe a feeling and emotion that would have been hard, if impossible, to capture otherwise.

Sarcasm is entirely destructive. It isn't comedy, and it isn't irony. I'm pigeonholing it into a very tight definition, but when sarcasm is used, it tends to be used as a way to put the person using it on a higher pedestal than whomever the sarcasm is directed at. I'm not sure if that makes sense, but think of times when someone acts in a sarcastic manner. It usually isn't funny, and it doesn't communicate a feeling, it's just meant to make a witty or kitschy point that is meant to bring the subject of the sarcasm down and elevate the person who is using sarcasm, his or her feeling of self worth.