Postmodernism is an academic theory, originating in academia with an academic elite, not in the world of women and men, where feminist theory is rooted.
Instead of being lionized and admired for her genius, instead of being able to earn a decent living as a writer, Andrea Dworkin was misrepresented and demonized.
Power is being able to say complete and utter nonsense and have it be believed, powerlessness is where no matter how much cogent evidence and proof one has, to not be believed.
To be a prisoner means to be defined as a member of a group for whom the rules of what can be done to you, of what is seen as abuse of you, are reduced as part of the definition of your status.
Imagine that for hundreds of years your most formative traumas, your daily suffering and pain, the abuse you live through, the terror you live with, are unspeakable - not the basis of literature. You grow up with your father holding you down and covering your mouth so another man can make a horrible searing pain between your legs.... You learn how to leave your body and create someone else who takes over when you cannot stand it any more. You develop a self who is ingratiating and obsequious and imitative and aggressively passive and silent - you learn, in a word, femininity.