Oroonoko Paragraph - Questions and Braveheart?

I'm a bit confused about specifically two things in this reading. The first is when Behn says, "I ought to tell you that Christians never buy any slaves but they give 'em some name of their own..." (2205). How exactly does that work? Unless I'm reading this wrong, this reads as if Christians are super in denial about slavery. The second thing that confuses me is at the bottom of 2205, where we're told that the slaves that Oroonoko comes across are the very same slaves he sold into slavery, yet here they are throwing themselves at his feet? Why would they do this?

I do have to say that calling Oroonoko Caesar is basically foreshadowing of when the slaves betray him later on in the story and his fate of death. Also, the ending of this story is giving me some serious vibes of Braveheart, what with the disembowelment, draw and quartering, and the refusal to live in under the rule of another.

.gif from Braveheart (http://media1.giphy.com/media/m12GiqBQywgbS/giphy.gif)