I disagree. I think it's very relevant. All five of your English examples are, after all, different words with different histories and intentions. The Japanese くそ does not have the same intention behind sht. Sht is explicitly vulgar in the majority of English speaking cultures. くそ is not vulgar in any Japanese culture.
Yes, I agree, "shit" is exclusively vulgar in English, and you only use it in casual context. That's why we're having this discussion in the first place. "Kuso" is not analogous to "shit" in all instances, this is where the concept of Japanese formal and informal language is important. English has no formality system since we dropped it in the 1600s, thus, we have no grammatical structures that are inherently vulgar in how you phrase sentences or words. We only have singled out crude words. I agree "kuso" is not 1:1 with "shit", because there is no 1:1 translation for "shit" in Japanese. Vice versa, there is no way to express Japan's formality system in English other than crude language, or for historical works falling back on shakesperean sounding language. Though, in the greatest of ironies, the "thee, thou" language associated with yesteryear is actually informal vulgar language, not formal language, which is what modern English is left with.
I would also argue くそ doesn't possess an intention for feces either, as the intention of feces in English is to abstract the crudeness of the object through a foreign language (i.e. Latin), so that it's "couth" to speak of in professional/medical circles.
I agree and literally pointed this out later with my comparison of "くそ (kuso) vs うんこ (unko) vs 糞 (fun)", "fun" being the equivalent of "feces". We both agree that context, history and other things matter. Not literal meaning. The fact that, literally, all of these Japanese words, and all of the English words listed (Shit, dung, excrement, poop, feces) refer to the same object is also something we agree on. It's the connotations of where it's used that matters. Let me restate, "kuso" is not 1:1 equal with "shit". Let's attack this from a different angle though. What is the most vulgar, informal way to refer to poop in Japanese? As far as any of my research, it's "kuso", nothing slides down more on the formality scale. If not "kuso", what word would you translate "shit" to in Japanese? Because it's not "うんこ" or "糞".
Ah, I'm glad you brought that last bit up. I'm not a fan of localization as it's commonly done. It's a form of censorship/watering down imo.
We agree on this explicitly. The problem literal translation problem tries to solve and localization tries to solve are two very different problems. However, there are certain contexts where translating literally is just obtuse. Again, to use an extremely vulgar example on the subject, translating a Japanese person having an orgasm as "I'm going, I'm going" instead of "I'm cumming, I'm cumming" benefits no one.
Whether it's changing the names of characters needlessly (Fire Emblem) or inserting mild language where there isn't any, I think it's silly, and you should instead port the original as faithfully as possible, linguistic quirks in all. Because then you actually pick up on how Japanese people think, and nothing is calqued or filtered out except basic parsing (it'd be weird if Japanese sentence structure was retained, as that'd be completely illegible in English 70% of the time).
I would agree, there are situations that are just silly, changing character names is a pretty stupid example of localization.
So that's probably where our perspectives primarily disagree. Since no Japanese person recognizes a "swear-tier" subset of words in their language, I don't think we should use any of ours to translate their words (unless, as stated before, they use one of our words for that purpose).
Again, I don't believe in localization unabashedly. If you're not going to localize to any degree though, how do you propose to capture Japanese thinking as far as formal language goes? There's no English equivalent to Japanese informal/formal scale. The conjugation changes, nouns change, but the words remain mostly the same give or take. The most basic example of this is that English has "you" (and used to have "thou") and Japanese has "omae", "anata", "kimi", "sochira", "kisama", "temee" and "onore", that is, when the Japanese even bother with pronouns. There's no literal way to translate these words differently. They all mean the same thing in English, "you". Yet you will lose a lot of context without some way of conveying tone and formality/vulgarity. We have to work with the tools given to us. Either you use English's closest equivalent to a formality system, the presence of lack of swears, or we need to engineer a formality system into the English to make translation in such a manner possible. The Japanese recognize vulgar speech, this can not be argued, what differs is how Japanese as a language executes vulgarity vs how English executes vulgarity.