physical abuse/ Rape scene in FFs

I have one question to all writers - Rape is the only incident that happens in any girl's life? life is full of incidents other than rape. then why every other F F has incident of rape?

either Hero's sister is gang raped, heroine's raped by someone or physically abused by hero, or someone just rape heroine or hero's sister to take revenge...

I am fed up with all these. I know that FF Forum has so many good writers who has capability to write story using any other incident of life than why most of the FF revolves around this topic?