Sinnott-Armstrong's argument conflates the belief's justification being supported by an inference with the belief itself being supported by an inference

With this jargon in hand they argue that Sinnott-Armstrong’s argument conflates the belief’s justification being supported by an inference with the belief itself being supported by an inference. Let U signify the undercutting defeaters for a moral belief, D the evidence that defeats these defeaters, and B the moral belief. Sinnott-Armstrong argues that for D to defeat U and thus restore the justification for B, D must provide the agent with a reason to believe that B was formed reliably. But, Ba