I have read the script at the link you gave and of course it is a sanatised version put out to try and counter this unnacceptable aspect of the Qu’ran.
Below is the wikipedia version which, I would suggest, is unbiased. And please note that all references to Muhammed freeing slaves was only after they converted to Islam - (no conversion - no freedom).
Slavery in the Qur'an (
http://en.wikipedia.org/wiki/Islam_and_slavery#Slavery_in_the_Qur.27an )
The Qur'an includes multiple references to slaves, slave women, slave concubinage, and the freeing of slaves. It accepts the institution of slavery. It may be noted that the word 'abd' (slave) is rarely used, being more commonly replaced by some periphrasis such as ma malakat aymanukum ("that which your right hands own"). The Qur'an recognizes the basic inequality between master and slave and the rights of the former over the latter. The historian Bruschvig states that from a spiritual perspective, "the slave has the same value as the free man, and the same eternity is in store for his soul; in this earthly life, failing emancipation, there remains the fact of his inferior status, to which he must piously resign himself."[3] [15] The Qur'an also recognizes concubinage.[16][17] A master may make his female slave as his concubine and, if she is a Muslim, he can marry her. Abstinence however is said to be a better choice.[2] The Qur'an urges, without commanding, kindness to the slave[18] and recommends, their liberation by purchase or manumission. The freeing of slaves is recommended both for the expiation of sins[19] and as an act of simple benevolence.[20] It exhorts masters to allow slaves to earn or purchase their own freedom (manumission contracts)."[16]
Slaves are mentioned in at least twenty-nine verses of the Qur'an, most of these are Medinan and refer to the legal status of slaves. The legal material on slavery in the Qur'an is largely restricted to manumission and sexual relations.[2] According to Sikainga, the Qur'anic references to slavery as mainly contain "broad and general propositions of an ethical nature rather than specific legal formulations."[21]
The Quran accepts the distinction between slave and free as part of the natural order and uses this distinction as an example of God's grace,[22] regarding this discrimination between human beings as in accordance with the divinely-established order of things.[2][23] "The Qur'an, however, does not consider slaves to be mere chattel; their humanity is directly addressed in references to their beliefs,[24] their desire for manumission and their feelings about being forced into prostitution.[25] In one case, the Qur'an refers to master and slave with the same word, rajul. Later interpreters presume slaves to be spiritual equals of free Muslims. For example,[26] urges believers to marry 'believing maids that your right hands own' and then states: "The one of you is as the other," which the Jalaalayn interpret as "You and they are equal in faith, so do not refrain from marrying them." The human aspect of slaves is further reinforced by reference to them as members of the private household, sometimes along with wives or children.[2] Pious exhortations from jurists to free men to address their slaves by such euphemistic terms as "my boy" and "my girl" stemmed from the belief that God, not their masters, was responsible for the slave's status.[27]
There are many common features between the institution of slavery in the Qur'an and that of neighboring cultures. However, the Qur'anic institution had some unique new features.[2] Bernard Lewis states that the Qur'anic legislation brought two major changes to ancient slavery which were to have far-reaching effects: presumption of freedom, and the ban on the enslavement of free persons except in strictly defined circumstances.[16] According to Brockopp, the idea of using alms for the manumission of slaves appears to be unique to the Qur'an, assuming the traditional interpretation of verses [Qur'an 2:177] and [Qur'an 9:60]. Similarly, the practice of freeing slaves in atonment for certain sins appears to be introduced by the Qur'an (but compare Exod 21:26-7).[2] The forced prostitution of female slaves, a Near Eastern custom of great antiquity, is condemned in the Qur'an.[14][28]Murray Gordon notes that this ban is "of no small significance."[29] Brockopp writes: "Other cultures limit a master's right to harm a slave but few exhort masters to treat their slaves kindly, and the placement of slaves in the same category as other weak members of society who deserve protection is unknown outside the Qur'an. The unique contribution of the Qur'an, then, is to be found in its emphasis on the place of slaves in society and society's responsibility toward the slave, perhaps the most progressive legislation on slavery in its time."[2]
Muhammad's traditions
The Islamic prophet Muhammad encouraged manumission of slaves, even if one had to purchase them first. On many occasions, Muhammad's companions, at his direction, freed slaves in abundance. Muhammad personally freed 63 slaves, and his wife Aisha freed 67.[30] In total his household and friends freed 39,237 slaves.[31] The most notable of Muhammad's slaves were: Safiyya bint Huyayy, whom he freed and married; Maria al-Qibtiyya, given to Muhammad by a Byzantine official, whom he freed and who may have become his wife;[32] Sirin, Maria's sister, whom he freed and married to the poet Hassan ibn Thabit[33] and Zayd ibn Harithah, whom Muhammad freed and adopted as a son.[3
