"Islam condones slavery"
This is one of the biggest lies that the Islamophobes spread about Islam. In fact, the exact opposite of this is true.
Not only is freeing a slave considered one of the most virtuous acts that a Muslim can do; but it's actually one of the means of expiation for many types of sins.
The expiation for breaking an oath is one good example:
“Allaah will not punish you for what is unintentional in your oaths, but He will punish you for your deliberate oaths; for its expiation (a deliberate oath) feed ten Masaakeen (poor persons), on a scale of the average of that with which you feed your own families, or clothe them or manumit a slave. But whosoever cannot afford (that), then he should fast for three days. That is the expiation for the oaths when you have sworn. And protect your oaths (i.e. do not swear much). Thus Allaah makes clear to you His Ayaat (proofs, evidences, verses, lessons, signs, revelations, etc.) that you may be grateful” [al-Maa’idah 5:89]
No wonder why I've never come across a 3rd generation servant through the texts that I've read; they all eventually get freed and this is what Islam came for (to eventually do away with slavery)