Are youth subcultures genuine signs of revolt or simply the manifestation of style?

Style is a big part of any form of subculture; as style is a means to show a different culture to that of their parents. That isn't to say that subcultures do not revolt, but they revolt through their own means; this often involves a sense of style unique to their own subculture.
"Subcultural youth, as the social Other to the parent culture, produce new codes and means of signification, new meanings and ways of meaning, which "take on a symbolic dimension, becoming a form of stigmata, tokens of self-imposed exile" (Hebdige, 1979)
In their style, poses, and general difference from mainstream values, subculture members aim to set themselves apart from the 'parent culture' as well as from other youth groups, for 'the communication of a significant difference is the point to the stylistic expressions of subcultures. Emphasizing their difference, subcultures make a "spectacle" of themselves, drawing attention to their difference. "Their look and activities announce an attempt to expose the myths of a homogeneous society and naturalized social consensus."
(Hebdige 1988) explains it quite clearly; "The 'subcultural response' is neither affirmation nor refusal, neither 'commercial exploitation' nor 'genuine revolt.' It is neither simply resistance against some external order nor straightforward conformity with the parent culture. It is both a declaration of independence, of otherness, of alien intent, a refusal of anonymity, of subordinate status. It is an insubordination. And at the same time it is also a confirmation of powerlessness, a celebration of impotence."