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.
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.
What postmodernism gives us instead is a multicultural defense for male violence - a defense for it wherever it is, which in effect is a pretty universal defense.
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.
So the idea that there is nothing essential, in the sense that there are no human universals, is dogma. Ask most anyone who is going to be shot at dawn.