Maybe I read too much history - but hasn't Big Sugar been known for "nothing that a slave trader wouldn't do" ethics for the past 300+ years?
Well, it's true that in the 17th century, sugar and rum production involved one of the most heinous forms of slavery ever to exist. What's not clear is that this necessarily has anything to do with the present; after all, slaves were emancipated a long time ago.
I think this is an instance of "large corporations in the 20th and 21st century have been intrinsically amoral" rather than "the sugar industry is intrinsically particularly evil (and has been since the 1600s)".
It is beyond me how anyone can expect any business (especially public traded) to have any ethics whatsoever.