In this post, I wrote: "The standard view ... obliterates distinctions between the ethics of that person, the ethics of society, and "true" ethics (whatever they may be). I will call these "personal ethics", "social ethics", and "normative ethics" ."

Using that terminology, you're objecting to the more general point that social utility functions shouldn't be confused with personal utility functions. All mainstream discussion of utilitarianism has failed to make this distinction, including the literature on the utility monster.

However, it's still perfectly valid to talk about using utilitarianism to construct social utility functions (e.g., those to encode into a set of community laws), and in that context the utility monster makes sense.

Utilitarianism, and all ethical systems, are usually discussed with the flawed assumption that there is one single proper ethical algorithm, which, once discovered, should be chosen by society and implemented by every individual. (CEV is based on the converse of this assumption: that you can use a personal utility function, or the average of many personal utility functions. as a social utility function.)