Sins don't apply to athiests or agnostics.
There are many things that don't make a rape court case straight forward. Like was the man lead on etc. More or less, the only thing I have a problem with is the forced physical attack and the mental upset that follows (or can follow). Some men, or even women, fantasise about rape without ever wishing to experience it.
Edit to VVD: In my opinion, the common aftermath of the event, the forcing of a human to partake in something that some believe to be quite a personal act, against her/his will.
-AC