Slavery was gotten rid of on the continent because they didn't need it for farming there anymore. They needed it in the colonies. Why does it matter where it's propagated?
"[Slavery] was established by decree of Almighty God...it is sanctioned in the Bible, in both Testaments, from Genesis to Revelation...it has existed in all ages, has been found among the people of the highest civilization, and in nations of the highest proficiency in the arts."
-Jefferson Davis, President of the Confederate States of America.
"There is not one verse in the Bible inhibiting slavery, but many regulating it. It is not then, we conclude, immoral."
-Rev. Alexander Campbell
"The right of holding slaves is clearly established in the Holy Scriptures, both by precept and example."
-Rev. R. Furman, D.D., Baptist, of South Carolina
"... under the same protection as any other species of lawful property...That the Ten Commandments are the word of G-d, and as such, of the very highest authority, is acknowledged by Christians as well as by Jews...How dare you, in the face of the sanction and protection afforded to slave property in the Ten Commandments--how dare you denounce slaveholding as a sin? When you remember that Abraham, Isaac, Jacob, Job--the men with whom the Almighty conversed, with whose names he emphatically connects his own most holy name, and to whom He vouchsafed to give the character of 'perfect, upright, fearing G-d and eschewing evil' (Job 1:8)--that all these men were slaveholders, does it not strike you that you are guilty of something very little short of blasphemy?"
-MJ Raphall, 1861
And Muslims during medieval times were deemed to be more humane and just than the Christians. Most minorities in Christian-ruled territories welcomed Muslim invaders because of this. They were seen as liberators.
