Just a moment here. Ratcho followers have no trouble explaining acting on principle. If one gets a lot of utility out of pursing principle, then a rational actor will do so. Ratch does not explain where people's preferences come from. I endorse Hiwatari-sensei's comments on the fact that rational choice should guide one to focus on interactions and choices among strategies, and it accepts the preferences as whatever the actor wants them to be.

Sloppy users of rational choice (including many economists much of the
time) have trouble remembering that utility and preferences need not be materialistic. An egoist pursues the egoist's preferences but those preferences can be anything.

Meg McKean