Thoughts Lead To Appreciation
First, the rule on slavery in pre-Islamic Arab society was non-racial.
Slavery was effective without bias for or against any race.
Zaid Bin Harithah was an Arab slave of Khadijah the wife of the Messenger Of Allah.
Thus, in the Arabian Peninsula, there were slaves of African, Persian and yes, Arab origin.
Pagan Arabs were just as egalitarian in the readiness with which they freed slaves.
Very wealthy Arabs were known for manumission of a large number of slaves.
One, Hakim Bin Hizam was recorded to have established the freedom of a hundred ~100 slaves. 
With the establishment of Islam in Medina, slavery was legalised, practised devoid of racial discrimination.
For instance, some of the conflicts between Muslims and other nations were either against Arabs or against Arabs as combatant allies of other aggressive nations.
In such situation, conquest took place along with the captivity of Arab opposition. 
Europeans were just as well taken captive during the numerous wars between Muslims and Christians.
African ~Black slaves retained their positive cultures, such as cultural displays and entertainment.
They publicly preserved and exhibited their traditions, which the wider community relished to watch.
Aishah the youngest wife of the Prophet was one who benefitted from such cultural carnivals. 
Her husband, the Messenger Of Allah, made certain she did not miss the opportunity.
It is crucial to understand that slavery in Arabia entailed acknowledging paternity of any child of a slave fathered by the slave owner.
Arabs did not hesitate to assume paternity of their sons  without consideration of the condition of birth.
Utbah Bin Abi Waqqas unsuccessfully sought to have custody of his son born to the slave-woman of Zam’a. 
In the ensuing legal custody battle, both families described the child as family.
The family of Utbah called the boy the “son of my brother”.
The boy was “my brother” to Zam’a’s family.
The practice of voluntary emancipation of slaves continued in Islam.
Contrary to Jahiliyy culture of inhumane treatment of slaves, Islam accorded captives egregious rights.
Among other rights, slaves have the right to negotiate and buy own freedom.
The transaction can be in monthly or yearly installments.
Slaves can also invite and enter into a pact with a third person to provide the funds towards freedom. 
Slaves have the right to education.
The education of female slaves is emphasised. 
A slave has rights to the same food and clothing as the master and to easy tasks, unless the slave owner wants to join in completing cumbersome duties. 
The rights of free persons were equal irrespective of race.
Every slave, African, Arab, Persian, European or Asian, was accorded equal regard.
To illustrate, the testimony of an African woman against an Arab was endorsed by the Messenger Of Allah. 
 Saheeh Bukhari: Volume 3, Book 46, Number 715
 Saheeh Bukhari: Volume 3, Book 46, Number 718
 Sunan An-Nasa’i: Volume 2, Chapter 34, Number 1595
 I have restricted this to sons as opposed to children, as it is possible girl daughters from slaves were rejected as daughters were generally perceived as a disgrace.
Of course, though prevalent was the practice of burying alive daughters, every household did not participate, as some women are known to have hidden their daughters.
 Saheeh Bukhari: Volume 3, Book 46, Number 710
 Saheeh Bukhari: Volume 3, Book 46, Number 713
 Saheeh Bukhari: Volume 3, Book 46, Number 720
 Saheeh Bukhari: Volume 3, Book 46, Number 721