No Universally Compelling Arguments has been put to me as a decisive refutation of Moral Realism, by somebody who thought the LW line was anti-realist. It isn't a decisive refutation because no (non strawman) realist thinks there are arguments that could compel an irrational person, an insane person, an very unintelligent person, and so on. Moral realists only need to argue that moral truths are independently discoverable by suitably motivated and equipped people, like mathematical truths (etc).