Apparently you did not read Avery Cardinal Dulles' article, a calm point-by-point supported rebuttal of John T Noonan's thesis along the lines of the somewhat less erudite version you're posting.

John Paul II did not comment on slavery in English, where the word "slave" without explanation means the only slavery the Anglo-Saxon tradition knew - chattel slavery.

In the Roman world of St Paul slavery was a class, a class with rights, standing at law, the right to buy freedom, and so on. In fact they had more rights than serfs did later, or immigrant factory workers did in 1880 in the USA.

Once you have read Avery Cardinal Dulles' "blather" we can pick this back up sans "JPII was overthrowing tradition", which folks have been pointing out to you is an error for at least three decades.