In interpreting Sacred Scripture, the Magisterium guides us to the Truth, not to adapt it to contemporary society. It is for contemporaries to accept the truth from the Magisterium; but this has not been popular for some five-hundred years or more.
Most of the conversation in this thread is made within a vacuum; all discussion of slavery for instance, is in the context of the post-enlightenment, mistaken notion, of the freedom of the individual, and then the idea is hybridized further with the super-enlightenment drug of the “American” idea of freedom. You will have to look long and hard in the Gospels to find any moral statement against slavery. Christ’s words to slaves are words to us; be content with your lot in life, be obedient.
In the pre-Christian west, slavery was a fact of life and had existed since beginning of recorded history, the Roman system of slavery is hardly comparable to the British/Dutch/American program that sprang-up illegally, against the direction of the Church and was a purely commercial enterprise. Though slavery was certainly condemned by the Church, even the galleys of the Holy League at Lepanto held some slaves of one degree or the other. I am quite sure that America’s abhorrence of slavery is based solely in its misguided ideas of freedom; for the American could there be a worse fate than to be a slave?
The high-priests of the Enlightenment have done yeoman work to convince us that the U.S. Civil War was over slavery, it is a simple matter to see that the Civil War was an economic war, just as every other war we’ve waged, and there are plenty of statements from blessed Abraham Lincoln to prove he didn’t give two hoots about slaves. Remember, this is a good Calvinist country that has even successfully Calvinised most of its Catholics, what else would we fight over but Money?