-snip again-
You might think I'm being anal here, but define "everyday use". Is it what, when I'm talking to strangers in person? My friends? My parents? Talking on the net? Each of these situations has different "catch-alls", and a different proportion of catch-alls to elaborations (because when I'm describing to my friends how atrocious the food in my canteen is, I sure as hell will elaborate). Note that I'm just accepting the whole "catch-alls vs. elaborations" dichotomy without complaining - even though there are causes for complaint, in theory.
After you've defined "everyday use", explain why the fact that some words don't fall under this definition makes them redundant. I mean, they are important for narrower contexts, within which you couldn't substitute them for catch-alls. I mean, "fucknugget" is just "person" with a negative value judgment attached to it (oversimplifying, but who cares). Now substitute it for "person" in the phrase "Eat shit and die, fucknugget". Do you, as a speaker of English, consider the result to have the same meaning as the original?
A dumb mechanical analogy is that if a part of a mechanism is way smaller than many other parts, that hardly makes it redundant. Language can communicate nuance when it is necessary. If it isn't necessary in all contexts, or even most of them (also a bit dubious), that doesn't mean nuance is redundant.
Okay.
I'd define "everyday use" as situations in which people communicate outside of the context of professional interactions, ceremonies, and situations involving court, officially sanctioned speechgiving, &c. That is to say: meeting friends from work for drinks vs. giving a presentation to coworkers and superiors, appearing in court vs. watching court TV with your family, meeting your company's CEO vs. meeting the owner of your favorite restaurant, talking about politics with friends vs. giving a speech on national television about the political climate, posting on a forum vs. writing an article for publication, &c. In other words, casual situations, the sort of interaction that is ordinary and routine.
And again, as I stated previously, the redundancy is one of practice rather than meaning (though PoH raises a relevant point)--any given person is unlikely to vary their vocabulary much, or think very hard about everything they say and the exact nuance of it.
The example you raised isn't actually accurate -- "person" doesn't remotely equate to "fucknugget". There's an intrinsic difference in meaning; one is both general and highly neutral, the other is obviously pejorative. It'd be more appropriate to compare "fucknugget" with, say, "asshole," "moron," or something else, in which case... yes, they're more or less equivalent. Profanity's one of the cases where there's relatively little shared meaning in the words, it's all about the tone and body language. You get vastly different meanings even from the same word if the context and related communication is different -- a stranger you just cut off in traffic shouting, "Fuck you, asshole!" while waving their fist vs. a close friend that you just teased laughing out the same phrase.
It sounds like we're basically saying the same thing, albeit from different directions and with a difference of opinion regarding one of the details (ironically enough): I specifically brought up more limited situations where variety in language is not only helpful but outright necessary: contexts in which you
need a fine degree of granularity in your communication. But that isn't day-to-day life (unless your life is entirely composed of complex work), and most people don't communicate with that degree of complexity all the time.
I think there's been a bit of a misunderstanding here: I'm not arguing "a complex vocabulary is superfluous in day-to-day life, ergo it is wholly redundant and can be safely discarded", but rather that in routine life it isn't
strictly necessary, and that people can communicate meaningfully without it regarding the typical subjects which arise in conversation in said life, and that it is therefore redundant
in those situations. Though, again, PoH's point is a good one, it shows the importance of the distinction between arguing that a deep vocabulary isn't necessary to communicate about basic subjects vs. arguing that a language doesn't need one at all. As per their example, three different people might greet others in three different ways which all equate to "hello" for their purposes, but it allows them to express their individuality and makes mundane conversation slightly more interesting.