History is filled with examples of how Christianity was used to either justify murder or racism or some wrong doing against another set of people. One can start with the Prostestians and Catholics as exemplified by the constant struggle between the Irish and the British Government.
Or consider the crusades (there were actually two crusades in the the middle ages) which were not a happy fest of preaching to the lost souls; instead, it involved outright war in which the "Holy Christians" were out to remove the Muslims who had taken over the Holy lands with force albeit they kinda failed.
Or consider the Spanish Inquirision in which the Jesuits used their power to wrongfully imprison and even burn at the stake those they fould quilty of commiting heresy...
Or consider the Salem witch hunt trials in the early 1600s in the town of Salem, Massachussetts where women and children (a few men if any at all) were actually burn ALIVE at the stake for supposedly being caught practicing witchcraft.
Or the fact that even in more recent times, the name of God/Jesus has been invoked to justisfy the act of war...need I say who?
In essense, as Ebonyrose was suggesting, I think that when it comes to human nature, we can and have use a form of higher power to justify doing wrong to a group of people somewhat differ from us in some form or the other and by that, no one offender should boast that their means and end is any better than that of the other...it is all wrong!
On touching slavery, the transatlantic journey was no cake walk by any stretch of the imagination...the movie Almstad gave us a mere insight into the perils that was experienced by the slaves along that fateful trip across the "great river". I mean being stalked up together tighter than sardines in chains sitting in vomit and feces does not seem like paradise. Not to talk less of the fact that these people were simply dumped in the ocean in chains and butt naked straight into the mouths of sharks and what not. No, this was not cool either and definitely not the nicer picture illustrated before.