It is a bit too highbrow for me, but if the argument is that "moral" is not a special sense of words, a moral "ought" is the same kind of "ought" as "this machine ought to be oiled", isn't that textbook consequentalism? Non-moral oughts are of course consequentialist - if oiling or not oiling the machine makes no difference, why bother?

No, it only seems that way to you because you implicitly assume consequentialism. Plato, for example, would argue that "this machine ought to be oiled" because an oiled machine better approximates the ideal form of a machine (in what we now call a Platonic sense).