I think it is what in social psychology is called "cognitive dissonance"- that is, when something happens to you that clearly contradicts the rules you lived by so far/what you believed in etc. you have to "make up" something that will adjust your new experience to your old beliefs. She couldn't have said "I wanted Roark" because she was strictly imposing on herself not to want anything- therefore she "makes up" in her mind that he raped her- since that would imply no desire of her own.
Jolie got a reaction from Myself in How does one justify the rape of Dominique in FH?