Hmm... I think Eliezer might have overstated his case a little (for the lay audience). If you take a utility function to be normative with respect to your actions, it's not merely descriptive of your preferences, for some meanings of "preference" - not including, I would think, the definition Eliezer would use.

Using more ordinary language, a Kantian might have preferences about the outcomes of his actions, but doesn't think such preferences are the primary concern in what one ought to do.