Fighting the oppression of cultural stereotypes related to keeping kesh is a bit different from fighting the oppression that led to the scalping of Sikhs during the times of Baba Banda Singh Bahadur.True but the Guru's also taught us to fight against oppression. Society's ideals, whether hair or another stereotype are a form of oppression.
One is fighting the oppression of cultural stereotypes when one stops doing what the oppressor, through criticism or through subtlety, coerces or inveigles one to do. One just stops, and takes the social consequences in stride.
That is the case when the stereotype comes from the drug culture, or from the fashion culture of anorexics, or any other realm of social ideals which are numerous and often contradictory. As long as an inner drama is raging, then anyone of us is still attached inwardly to the stereotype, and not free of it.