This may be a question that only one who practices this ritual could answer. A lot of people would say it is an artistic expression and a sign of creativity. I used to buy that one, but I believe that artistic expression only goes so far. There is a fine line that exists between artistic expression and societal protest. I guess that it is a personal judgment call when somebody has crossed that line, but I believe the line is crossed when the unusual looking person walks down the sidewalk and catches glances from all directions and breaks all conversation.
Artistic expression sparks fads and societal protest sparks concern.
I don't see an enormous crowd going out in public with eyebrow rings and green hair, so it must be protest. If its just attention they want, they certainly have it. If they want society to change, you don't do it by becoming a societal outcast. Commanding respect and sending a dignified message would be a much better alternative. I feel sorry for those that are struggling with personal identity or that feel our society is inadequate for them, but the problems that they are going through are not going to get any better if you don't try to adjust to it.