Speculation time (not a linguist): I think this is an inherent problem in human languages, they're fundamentally not sophisticated enough to communicate nuances. We see this all the time in engineering, politics etc. People always talk in terms of rules because these are easier to phrase, but in reality everyone takes every decision situation-by-situation basis. But then when you need to explain these nuances, you simply need to use more words.

I think this also makes sense. Take a cat. Cats clearly are able to think a lot more complex than they can communicate. They use a set of very basic body cues to communicate, but they are able to process information a lot more complex than these. Why would this not be like this humans too?

I have some very opinionated friends on coding styles, libraries, programming languages, programming "rules", "principles" etc... They're all sort of rubbish. I think it's important to know and study them because they give you different ways to think of engineering. But when it's time to commit code to production does anyone really think about "ah this is not DRY, premature optimization, NIH etc...". I claim no. We always think about the specific situation. Is it good to invent this code. Is it good to optimize this possible future extension. Is it good to repeat this particular code. We all know repeating code is "bad" but we all also know reasonable exceptions.

So yes, all rules are by nature fuzzy. In fact, whenever someone tells me a principle they hold, I immediately start thinking about fuzzy-fying it i.e. thinking of possible niche cases where this principle would reasonably NOT hold.