I would suspect Allah is ok with slavery because he was ok with it in the OT.
Well I don't want to comment about OT here as this out of the scope of this thread but ALLAH (swt) didn't condone nor support slavery in Qur'an . Rather we have verses in Qur'an where ALLAH (swt) encouraged to support and to give freedom to the slaves :
[002:177] It is not righteousness that ye turn your faces Towards east or West; but it is righteousness- to believe in God and the Last Day, and the Angels, and the Book, and the Messengers;
to spend of your substance, out of love for Him, for your kin, for orphans, for the needy, for the wayfarer, for those who ask,
and for the ransom of slaves; to be steadfast in prayer, and practice regular charity; to fulfil the contracts which ye have made; and to be firm and patient, in pain (or suffering) and a dversity, and throughout all periods of panic. Such are the people of truth, the God-fearing.
[004:092] Never should a believer kill a believer; but (If it so happens) by mistake, (Compensation is due): If one (so) kills a believer, it is ordained that
he should free a believing slave, and pay compensation to the deceased's family, unless they remit it freely. If the deceased belonged to a people at war with you, and he was a believer, the freeing of a believing slave (Is enough). If he belonged to a people with whom ye have treaty of Mutual alliance, compensation should be paid to his family, and a believing slave be freed. For those who find this beyond their means, (is prescribed) a fast for two months running: by way of repentance to God: for God hath all knowledge and all wisdom.
[005:089] God will not call you to account for what is futile in your oaths, but He will call you to account for your deliberate oaths: for expiation, feed ten indigent persons, on a scale of the average for the food of your families; or clothe them;
or give a slave his freedom. If that is beyond your means, fast for three days. That is the expiation for the oaths ye have sworn. But keep to your oaths. Thus doth God make clear to you His signs, that ye may be grateful.
[058:003] But those who divorce their wives by Zihar, then wish to go back on the words they uttered,- (It is ordained that such a one)
should free a slave before they touch each other: Thus are ye admonished to perform: and God is well-acquainted with (all) that ye do.
In fact the following verse straight-away commanded that if the slaves ask for deed for freedom from their masters , they should be given the freedom and also to provide them wealth so that they can seek establishment in the society :
[024:033] Let those who find not the wherewithal for marriage keep themselves chaste, until God gives them means out of His grace.
And if any of your slaves ask for a deed in writing (to enable them to earn their freedom for a certain sum), give them such a deed if ye know any good in them: yea, give them something yourselves out of the means which God has given to you. But force not your maids to prostitution when they desire chastity, in order that ye may make a gain in the goods of this life. But if anyone compels them, yet, after such compulsion, is God, Oft-Forgiving, Most Merciful (to them),