How do you define anarchy? Is it about no government or no “unjust hierarchies” for you?
First, let me say that I am only speaking for myself, and not for any organization, or any movement as a whole. I would define anarchism as a form of social organization that is based on individual autonomy and voluntary association in the absence of the state. As for the question of hierarchy, I think it is necessary to differentiate between voluntary and coercive hierarchies, natural and artificial hierarchies, and superfluous hierarchies and hierarchies that might serve some legitimate pragmatic purpose.
An example of voluntary hierarchy would be when an individual chooses to embrace the rigors of a monastic lifestyle or a disciplined sports team. A coercive hierarchy would be a conscript army, a prison, or a state system that imposes a particular set of values by authoritarian means such as the threat of death, imprisonment, or expropriation.