What is the author's tone in the novel, Oroonoko?

In spite of apparent efforts to make the piece’s narrative voice compassionate and enlightened, there is a strong sense of the lecture about it (i.e. that the narrator / author is instructing the reader on a form of morality), of the condescending and the patronizing. There is also the concurrent sense of agenda in the narration: that she is writing not necessarily to enlighten and not even to instruct, but on some level to shame – specifically, to shame those who think like the less-enlightened (primarily white) characters in the story into feeling badly about what was done to Oroonoko and, by extension, individuals in the non-narrative world who are treated in the same way … as dehumanized slaves.