The notion that slavery was a permissable source of self-righteous indignation that justified terrorism and slaughter on an industrial scale can be laid at the feet of the Unitarians. The British empire abolished slavery over the course of 20 years, providing funds to aid in the transition. Today, a disproportionate percentage of black professionals in the real disciplines (excluding govt. work and including medicine and engineering) are of "west indian" origin. In the States, it took the death of 600,000 Americans to achieve that goal, and several decades of military occupation to make it stick.
It was unitarian money that bankrolled domestic terrorist John Brown's slaughter of innocent folks who offered him hospitality (See Otto Scott's meticulously documented book The Secret Six). It was unitarian propaganda that framed human sacrifice as a legitimate substitute for the atonement of Christ. The "Battle Hymn of the Republic" views the union armies as a new incarnation.
We're still suffering the effects of the New England apostasy, that saw church after church take the cross off the steeple and replace it with the weathervane.
How can you preach about the evils of slavery by using the bible? I am curious....not a baited question at all.