I remember a couple years ago there was a story in Somalia about some men being convicted of gang rape. They were giving a sentence of "caning"...which actually only amounted to them being hit with thin reeds over their clothes. The men were actually laughing and joking as they were being hit.
This was contrasted to the case of a 13 year old girl in Somalia who, a year or two earlier, had been stoned to death as punishment for being gang raped.
I don't really know how you come to the conclusion that being raped is a worse crime than raping someone. My *guess* is that the assumption is that the girl must have done something which drove the men to rape her, so the blame ultimately lays with her. Or maybe its just that being raped dishonors your family/community, while raping someone, for whatever reason, does not. So the girl has to be murdered but not the rapists because she's the only one whose continued existence brings dishonor and shame to their community. I've heard news stories about women in Islamic fundamentalist communities who were raped who were either murdered by their families or told they needed to commit suicide, in which the girl was not considered to be "at fault" for the rape... but she still needed to die to uphold the family honor.