The tyranny of structurelessness
From Jo Freeman's essay on group structure:
A laissez-faire group is about as realistic as a laissez-faire society; the idea becomes a smokescreen for the strong or the lucky to establish unquestioned hegemony over others.
This hegemony can easily be established because the idea of "structurelessness" does not prevent the formation of informal structures, but only formal ones.
Also this:
The characteristic prerequisites for participating in all the informal elites of the movement, and thus for exercising power, concern one’s background, personality or allocation of time. They do not include one’s competence, dedication to feminism, talents or potential contribution to the movement.