So it doesnt matter whether yiuur sisters or adult daughters WANT to have sex and are not interested in a long term relationship with the guy either, you will "fight" to prohibit that?
No that isn't happening actually,girls in our society are well taught to protect themselves from dirty men whom just looking for girls for their sex desires and even that also taught in schools plus there are morality police around schools to protect school girls from such dirty men.
So in our society praise to god we don't have such cases,but what if your daughter at age of 10 years and wanted by her own desire to have sex with a young boy,what you will do in this case ?
You may stop her to do so at that age and you may even call the police to claim that such and such are trying to fool your baby,but what if she is at age 15 or 18.
She isn't any more a child and any one is allowed to have sex with her if she wanted to.
But for us we treat them as children till the day that they are married.
i know that it is normal maybe in your society to have such relationship between young boys and girls but that isn't the case in muslim societies.
i think that is taught by religion because we have also christians in our society whom are less strict on such matters and even if we go back to pre-islamic arabia (Jahiliyyah) we find out a society where everything was allowed,killing,stealing,rapes,hard drinks,adultery,women slaves and that all have been changed as a miracle by prophet Mohammed PBUH.
The society variations can be well noticed by reading the history of the Arabs before Islam and the same Arabs after Islam ,from ignorance to a great empire.