This debate has been floating around for a bit. It deserves a bit of light, a bit of mediation, and a few more people to participate to fully grow into something. I'm going to say straight off the bat, I don't think style is relative. It can be defined and it is not dependent on the beholder. Would you not agree that a good artist is someone who effectively conveys his message though some medium? If I wanted my picture to convey a message of violence and everyone sees it as sadness, then I am not an effective artist. If you aim to dress well but everyone sees it as slobby, then you failed to convey the message that you are a well dressed person. I could continue, but others have walked these paths.
Jon Moy presents the argument for relative, though is by no means, a complete relativist.
Die, Workwear! presents a piece arguing for a set taste as he is arguing that style is not relative.
It should be noted that both authors are not black and white on this issue (based off their other written pieces), and that this issue is not black and white either.