In reply to #10:
That's a very keen point you've touched there. Slavery used to be a way for people to "pay off their debt" in much of the ancient world. In fact, such was also the nature of African slaves (in the beginning). After working off their debt or work for capture, slaves were allowed to "free" themselves. However, with the trans-atlantic trade system and the changes in the slave system by Europeans, the very nature of slavery transformed into something more sinister and well, RACIAL. This guilt, as you have said, is manifested in post-Enlightenment mentality of the moral aspect of the institution.
Furthermore, this moral hazard became much more apparent because slavery was a practice that ruled against the Christianity (something about how all men are equal before God). But to justify their trade, the slave traders (Dutch if I recall correctly) developed the idea of racism: that, black man is not human, but sub-human, and therefore NOT equal.
I must, however, argue that your last argument is much too idealistic. The fundamental reason why slave trade does not cease is because the human body is the last line of credit. One can "sell", in essence, his or her body when all else fails. And desperate moments call for desperate measures. Unless we can solve world hunger, poverty, disease, and the many like problems of inequality, there will always be slavery.
