I would say that socially comprehensive ethical knowledge exists, of which any individual is free to avail themselves. Many of our concepts have vague boundaries, this is a painful facet of very crucial concepts. Ethics as knowledge. Ethics is a distinctive type of knowledge. Mistakes in grammar, chemistry, or math are usually of minor consequence and readily forgiven.
Ethical errors are, if severe, often unforgiveable and a sign of character disorder.
Moreover immoral deeds are generally done in complete awareness of their immorality. Perhaps only a Post-modern or a follower of Dostoevsky would persist in knowingly commiting unbeneficial blunders in math. Serial killers are probably not in need of new knowledge about ethics. The prevalence of immmorality in the world is to be remedied by improving child rearing, not by offering more courses in ethics. Evil derives from social pathology not epistemological deficiencies.