Islam provides practical solutions to life's issues. Whether you like it or not war involves the wholesale ravaging of the womenfolk by the conquerors. This happened in the past and will continue to happen. One just needs to look at conflicts including the recent past and the treatment of women caught in the crossfire of war.
The lady who is taken as captive in Islam does not have the right to refusal however, her master is unable to assault her to fulfil his desires. If he does so he has acted with zulm which is a grave sin punishable by Allah
Also there is a whole category of Islamic jurisprudence deatiling on how this lady is treated and if she becomes pregnant with the master's child then she will become his umm walad on his death. As far as I know even the child born from this union has a share in the inheritance of his father.
Please also bear in mind that a whole nation's women will not be treated as slaves but only those that have been captured on the battlefield or if a city has been stormed by force.
Allah Ta'ala provided the Muslims with a perfect Rasul who was the embodiment of true moral character. Please read how he treated the women 'slaves' that were his by right. Some of them became the most respected women on the planet known divinely as 'ummul mu'mineen - Mother of the Believers.'
You are looking at this through the poisoned prism of western 'ideals' and supposed 'morality' which if objectively viewed is nothing but ignorance.
You also forget that of paramount importance in Islam is the accountability that he/she will face when he/she meets his Creator on the Day of Judgement.
Wa maa alayna illal balaaghul mubeen - And upon us is to only convey the plain message - Surah Yaseen, Al Qur'aan.