"I hope you share my intuition that utilitiarianism is an unusually thing-oriented and systematizing moral system, and that this gestures at the same large but hard-to-explain difference as the other two results."

I do not. Utilitarianism, at its core, is the exact opposite of "thing-oriented" - it treats rightness of action as a function of the action's good, rather than as a property of actions. In the (act) utilitarian view, something is not good or bad in and of itself - it is only good or bad with respect to its consequences. As such, an act utilitarian should give no mind to "things" themselves, but only to the actions that produce the best outcomes.

Edit:

I enjoy reading SSC, but I think Scott Alexander (and the normal rash of new utilitarians) consistently make the same mistakes that their positivist progenitors made in the 1940s. I wish we (academia, and society as a whole) would stop treating science and human concerns as prickles and goo[1].

[1]: https://www.youtube.com/watch?v=D4vHnM8WPvU