The validation thing is legitimate. Basically how this works is that a lot of times when someone experiences rape, they desperately want to feel like it was something "more" or "different," and so they pursue additional encounters with the person, in order to make the rape into part of a relationship or at least to make it feel more like (in their head) part of a consensual interaction. The human mind really, really hates to feel like it doesn't have control over any situation, even when it's abundantly clear that it doesn't.

Sometimes people don't like to call their experience rape. Legally, if someone overcomes you physically or through threats, or intimidation, that's considered rape.

Of course she is going to react with anger or hurt when you question whether her rape experience is real. Considering how shitty society treats rape victims, practically everyone is up in their face about "why didn't they do this or that" or "are you sure it was rape." The fact is, if a rapist intends on raping a person, they often can do so. A person determined to commit a crime is often going to succeed, unfortunately. Responding by picking apart their victim is counter productive to the victim's healing process, and in fact shifts the focus of accusation from the actual criminal onto the person who was hurt by them. That is a terrible way to go about things, but it's easy for people because nobody wants to believe that you can so easily be taken advantage of.