@Oukishi I was thinking about that. Perhaps it has to do with how the Western concept was carried over to East Asia. The first kanji in
rinri means "ethics, principles, duty, rules". It might have something to do with the fact that the Greek root
ethos means "character, nature", but also "custom, usage". (https://logeion.uchicago.edu/%E1%BC%A6%CE%B8%CE%BF%CF%82)
Down to the bare bones, "ethics" might be understood as the knowledge of "how to live". Which may bring it very close to what is more broadly understood as Philosophy. The study of animal behaviour, Ethology, shares the exact same root. Ethics might be just human Ethology 🤣
(I am aware that is not how we define Ethics academically; I'm just saying that East Asian understanding of Western Ethics may conflate it with other areas of Philosophy. And in any case, this is just speculation.)