Utilitarianism as used on LW typically refers to something closer to "It is in my personal nature to act as to maximize the average amount of [list of types of computation] minus [list of other types of computation] of entities that [qualification criteria]" where the contents of the brackets vary from person to person and are extremely complex, not "everyone objectively should maximize 'happiness' ".

Note that's "closer" not close; this is a one-sentence oversimplification.