This reminds me of a bit in The Righteous Mind, where Haidt discusses some of his experiments about moral reasoning. When he asked his university students questions like "is it right or wrong for a man to buy a (dead) chicken from a store and then have sex with it before eating it", the students had no problem providing a long list of various justifications pro or con, and generally ending up with an answer like “It’s perverted, but if it’s done in private, it’s his right”. In contrast, when Haidt went to a local McDonalds to ask working-class people the same questions, he tended to get odd looks when he asked them to explain why they thought that the chicken scenario was wrong.

Haidt puts this down to the working-class people having an additional set of moral intuitions, ones where e.g. acts violating someone's purity are considered just as self-evidently bad as acts causing somebody needless pain, and therefore denouncing them as wrong needs no explanation. But I wonder if there's also a component of providing explicit reasons for your actions or moral judgements being to some extent a cultural thing. If there are people who are never asked to provide justifications for their actions, then providing justifications never becomes a part of even their internal reasoning. If we accept the theory that verbal reasoning evolved for persuasion and not for problem-solving, then this would make perfect sense - reasoning is a tool for argumentation, and if you never need to argue for something, then there's also no need to practice arguments related to that in your head.

Actually, Haidt does seem to suggest something like this a bit later, when he discusses cultures with a holistic morality, and says that they often seem to just follow a set of what seems to be (to us) ad-hoc rules, not derivable from any single axiom:

Several of the peculiarities of WEIRD culture can be captured in this simple generalization: The WEIRDer you are, the more you see a world full of separate objects, rather than relationships. It has long been reported that Westerners have a more independent and autonomous concept of the self than do East Asians.3 For example, when asked to write twenty statements beginning with the words “I am …,” Americans are likely to list their own internal psychological characteristics (happy, outgoing, interested in jazz), whereas East Asians are more likely to list their roles and relationships (a son, a husband, an employee of Fujitsu). [...]

Related to this difference in perception is a difference in thinking style. Most people think holistically (seeing the whole context and the relationships among parts), but WEIRD people think more analytically (detaching the focal object from its context, assigning it to a category, and then assuming that what’s true about the category is true about the object).5 Putting this all together, it makes sense that WEIRD philosophers since Kant and Mill have mostly generated moral systems that are individualistic, rulebased, and universalist. That’s the morality you need to govern a society of autonomous individuals.

But when holistic thinkers in a non-WEIRD culture write about morality, we get something more like the Analects of Confucius, a collection of aphorisms and anecdotes that can’t be reduced to a single rule.6 Confucius talks about a variety of relationship-specific duties and virtues (such as filial piety and the proper treatment of one’s subordinates).

If WEIRD and non-WEIRD people think differently and see the world differently, then it stands to reason that they’d have different moral concerns. If you see a world full of individuals, then you’ll want the morality of Kohlberg and Turiel—a morality that protects those individuals and their individual rights. You’ll emphasize concerns about harm and fairness.

But if you live in a non-WEIRD society in which people are more likely to see relationships, contexts, groups, and institutions, then you won’t be so focused on protecting individuals. You’ll have a more sociocentric morality, which means (as Shweder described it back in chapter 1) that you place the needs of groups and institutions first, often ahead of the needs of individuals. If you do that, then a morality based on concerns about harm and fairness won’t be sufficient. You’ll have additional concerns, and you’ll need additional virtues to bind people together.

One might hypothesize that moral systems like utilitarianism or Kantian deontology, derived from a small set of logical axioms, are appealing specifically to those people who've learned that they need to defend their actions and beliefs (and who therefore also rationalize) - since it's easier to craft elaborate and coherent defenses of them. People with less of a need for justifying themselves might be fine with Analects of Confucius -style moralities.