Human Scum - The people who trafficked in human souls over 135 years ago are already paying for their sins if they did not repent and throw themselves upon the mercy of God through the substitionary death of Christ. As Jesus said, they already have their reward.
That said, I cannot find words strong enough to condemn the moral bankruptcy of the people in this story who attempt to profit from their ancestors' slavery.
Reprehensible, revolting, disgusting and vile come to mind immediately.
They violate the Law of God by breaking at least the 8th, 9th and 10th commandments, but I suspect that idolatry is also involved, violating the 2nd commandment, and they certainly bring shame on their parents, thereby violating the 5th commandment.
The lawyers who brought this suit should be disbarred and publicly reprimanded for wasting the time of all parties involved. I was going to say they should be publicly humiliated, but anyone this shameless is obviously incapable of experiencing so cleansing an emotion.