Granted, Utilitarianism is a broad and variegated beast, and I’m no expert on the tradition. But every form of Utilitarianism I’m familiar with (again, a limited set) treats happiness as a quantifiable outcome, and treats people as standardized or standardizable units. I have not heard of any that have any interest in “growing people’s hearts” in any direction at all. That sounds more like virtue ethics to me.

On the other hand, the reduction of every person and every good to a variable for plugging into a calculus does sound rather dehumanizing, with potential for Grinchian actions.

Could you point out to me what I am missing in understanding Utilitarianism?

…the choices before us drearily compact into dark and Grinchly caves of icy utilitarianism…

Utilitarianism is the opposite of Grinchism. Most people are born with hearts several sizes too small that only allow them to value friends, relatives, and people physically near them. Utilitarianism tries to grow people’s hearts towards an ideal of caring about everyone.