@Woodrow - to answer your question about why I think they were sex slaves...
70:29-30 Says that men should guard their (private parts) except from their wives and slaves.
Here are as many tafsirs as I can find for verse 30:
Al Jalalayn: and those who guard their private parts, except from their wives and those whom their right hands own, in the way of slavegirls, for in that case they are not blameworthy;
Ibn Kathir: they keep their private parts away from that which is forbidden and they prevent their private parts from being put into other than what Allah has allowed them to be in. Except from their wives or their right hand possessions, meaning, from their female slaves.
23:5-6 Also tells men to guard their private parts again with the exception of their wives and slaves
Al Jalalayn : and who guard their private parts, against what is unlawful, except from their spouses, that is, to their spouses, and what [slaves] their right hands possess, that is, concubines, for then they are not blameworthy, in having sexual intercourse with them.
Ibn Kathir: means, those who protect their private parts from unlawful actions and do not do that which Allah has forbidden; fornication and homosexuality, and do not approach anyone except the wives whom Allah has made permissible for them or their right hand possessions from the captives. One who seeks what Allah has made permissible for him is not to be blamed and there is no sin on
him.
My first impression when reading these verses was that the Quran is not talking about marriage because X is forbidden except from your wives and slaves. X could not be marriage because the idea of saying "you are free to marry your wives" makes no sense. Whatever X was it was permissible
A: With your wives
B: With your slaves (and then only for men with female slaves, I cannot find the same permission for women.)
I am a fair and objective person and will at this point concede a point
The point I will concede is that releasing all of the slaves in one go may have been disastrous as many were men who had fought against the Muslims in war. Releasing an army to go back to their home ground where they could make more weapons could have been a very bad choice (putting aside of course the claim that the Muslims say they had the most powerful entity in existence fighting on their side.)
The points I have yet to concede are
1: Many men were ransomed back to their families, so what's the difference? Receiving some money from their families does not change the slaves intended actions when he gets home.
2: Some slaves were women and children who had not fought in battles against them, these could have been released without risk.
3: If Allah wished for those female + child slaves to be released then Allah "the nourisher" could have provided for these people. Who needs a human man to provide for them when it is the creator of the universe which wants you to be free and provided for?
So the most important point I am yet to concede is
4: Why would Allah give permission for men to have sex with them?