I think most people will agree that a man who rapes a prostitute should get less punishment than if he raped an ordinary woman. Why is that? Because, aside from the physical assault, the man is not really doing anything to her that has not been done to her before. I mean the sexual aspect. She's already had sex with hundreds of strange men she didn't really know and wasn't very choosy about. One more isn't that terribly big of a deal, when viewed from that perspective.
There is a gulf of difference between the perspective of conservatives and those of progressives. Should perhaps rapists receive more punishment if he has taken the girl's virginity? Especially if she comes from social circles where she is likely to try to save her virginity until marriage. (And not even just virgins, but perhaps married women, if they have never had sex with any other man besides their husband before)
It's true there may be some problematic issues with courts trying to determine whether she is a virgin, but there are several indicators that can be used to determine whether that's probably the case, and of course we would have to rely on the information from the woman too. (I don't think most women will lie about this. Most women to whom virginity is not a big deal will be satisfied as long as the rapist gets punished with many years in prison) In fact, I think many judges already do this, informally. They secretly take it into account in factoring the sentence. But maybe we should more overtly codify it into law.