This essay makes a correct appraisal of Less Wrong thinking, but it denominates the position confusingly as "natural rights." The conventional designation is "moral realism," with "natural rights" denoting a specific deonotological view.

A more charitable reading than than provided by commenters would have understood that all the arguments invoked against natural rights (as well as the arguments attributing natural-rights thinking to Less Wrong) hold for other forms of moral realism, in particular utilitarianism/consequentialism. For an argument that utilitarianism is necessarily a form of moral realism (and other problems with utilitarianism) see "Utilitarianism twice fails".

In short, substitute "moral realism" for "natural rights."