I think we need to factor in "Correlation is not causality" and the presence of confounding variables.
Slave abolitionists explicitly mentioned where they derived their morals from - clearly establishing causality.
Could there be something else common among slave practitioners apart from religion - like common materialistic greed and superior firepower to overpower and dominate others?
> Could there be something else common among slave practitioners apart from religion
Cherry picking again, are we? So now we are looking for an alternative explanation - but only on the evil side. The existence of Christians who opposed slavery does not prove that it is in any way central to Christianity, or exclusive to Christianity. That's not how logic works.
On the other hand, the humanist Enlightenment in France led to the French revolution, led in turn to laicist France granting citizenship to former slaves in 1792 on non-religious grounds.
So yeah, there was something else among both abolitionists and slave holders, which is my whole point.
Slave abolitionists explicitly mentioned where they derived their morals from - clearly establishing causality.
Could there be something else common among slave practitioners apart from religion - like common materialistic greed and superior firepower to overpower and dominate others?