The LORD has the final say in this matter.
The Church will not tell you that something sinful is not sinful no matter how much you want to believe it.
June 20, 1866, the Holy Office (now called the Sacred Congregation for the Doctrine of the Faith) issued a statement that said:
"Slavery itself, considered as such in its essential nature, is not at all contrary to the natural and divine law, and there can be several just titles of slavery and these are referred to by approved theologians and commentators of the sacred canons.... It is not contrary to the natural and divine law for a slave to be sold, bought, exchanged or given.
December 5, 1484
"[m]any persons of both sexes, unmindful of their own salvation and straying from the Catholic Faith, have abandoned themselves to devils, incubi and succubi, and by their incantations, spells, conjurations, and other accursed charms and crafts, enormities and horrid offences, have slain infants yet in the mother's womb, as also the offspring of cattle, have blasted the produce of the earth, the grapes of the vine, the fruits of the trees, nay, men and women, beasts of burthen, herd-beasts, as well as animals of other kinds, vineyards, orchards, meadows, pasture-land, corn, wheat, and all other cereals; these wretches furthermore afflict and torment men and women, beasts of burthen, herd-beasts, as well as animals of other kinds, with terrible and piteous pains and sore diseases, both internal and external; they hinder men from performing the sexual act and women from conceiving, whence husbands cannot know their wives nor wives receive their husbands; over and above this, they blasphemously renounce that Faith which is theirs by the Sacrament of Baptism, and at the instigation of the Enemy of Mankind they do not shrink from committing and perpetrating the foulest abominations and filthiest excesses to the deadly peril of their own souls, whereby they outrage the Divine Majesty and are a cause of scandal and danger to very many (...) the abominations and enormities in question remain unpunished not without open danger to the souls of many and peril of eternal damnation."
Let's burn witches and keep slaves. The church, who wouldn't tell us that something sinful wasn't... says it's ok.