I see what you're saying, Laser Beam, but there's also another side to this. Clearly the slave owners/kidnappers can't be excused for what they did. However, let's say the slaves rise up and not only free themselves, but also decimate the slave owning population. They set up their own government, and in the process deny by law all rights to the former slave holders, including the right to literacy, for the next several generations.
The former slaves would regard the former slave holders historically as evil and deserving of their fate, and would consider themselves in modern day as heroes. The former slave holders would consider themselves in modern day as oppressed victims, and the former slaves historically as butchers. Both sides are working off their own perceptions, with the slaves decendants not wanting to lose the upper hand (and ensuring that through law), and the slave holder descendants feeling oppressed because they themselves did nothing wrong. Both sides are so entrenched in their roles that their society has literally stagnated.