Difference between 'Redundant' and 'Superfluous'

(I made a search for this question on this forum but surprisingly did not find related questions. Which is odd because surely this question is asked often.)

First, the sentence I'm trying to use redundant/superfluous in:

From what I know, fiction is created from fantasy by people you call authors. At the risk of sounding discourteous let me say that I do not trust fantasies. Life is not a fabrication played out on stage. This is why I feel people who write fiction are redundant. I myself never speak of things I have not experienced firsthand.

I was told that 'superfluous' would be a better word choice in place of 'redundant' because using 'redundant' would suggest that the speaker is scornful of only those 'authors' who are 'extra' when he is scornful of 'all' authors. But using 'superfluous' here sounds simply odd to me.

OED gives the definitions of the two words as:

redundant (adjective) - not or no longer needed or useful; superfluous: an appropriate use for a redundant church many of the old skills had become redundant

superfluous (adjective) - unnecessary, especially through being more than enough: the purchaser should avoid asking for superfluous information

This site explains them as:

Superfluous (from Latin, and literally meaning “overflowing” — the second part of the compound is related to fluid) means “extra, more than is necessary.”

Redundant has the same literal meaning as superfluous — the second part of the compound is related to wave — and the identical basic connotation, though it also has the senses of repetition, abundance, or extravagance, or duplication as a safety measure.

The more I try to dig into the meanings and connotations of these words the more I'm left confused. Any inputs on this?

"Redundant" involves repetition. In the following example, there are two examples of redundancy: "This blue, azure shirt is torn and ripped." Blue and azure are redundant, and torn and ripped are redundant. Note that these redundancy pairs do not include words that are exactly synonymous, but which are close enough in meaning that one would usually consider them redundant. Two points here: 1. Neither word in such a pair is necessarily the redundant one; either one can be considered redundant, depending on which one you consider to be the more important, useful, or accurate one in the given context. Commonly, the second word is considered the redundant one, but that is merely because the first word got a chance to establish itself before the second one came along; if you were revising the text, you might choose to keep the second, not the first. 2. The same word repeated ("this blue blue shirt") is an example of redundancy, but this is usually done for emphasis, or for poetic effect, and so is seldom saddled with the accusation of redundancy. Thus, "redundant" does tend to carry the implication of an unnecessary repetition.

A tip: To help you remember this, note that "redundant" begins with "re," as in "repetition." That piece of these words means "again."

"Superfluous," on the other hand, refers to something that is more than what is necessary. Think of water running over the rim of a glass when you continue to pour water into it beyond its capacity. The water over- (super) flows (fluous). Often something superfluous is so because it is needlessly repetitive, and this confuses the picture a bit. But in my opinion, "superfluous" is better used when the element is not repetitive, but is genuinely not needed, as in this example: "After George embedded the fence post in thirty pounds of concrete buried underground, the brick he balanced atop the post to hold it down was superfluous."

Sometimes redundant and superfluous are not interchangeably synonymous. Language, for example, is filled with redundancies because people feel that they're necessary, not superfluous. It's clear from looking at these images of No Smoking signs that including both the words and the image is redundant, but it should also be clear that it's not necessarily superfluous: some people can't read English, and others may not understand the icon.

Your use of redundant in the example sentence is, I think, not correct, and whoever said that superfluous is "a better word choice" is correct, IMHO.

If you believe that there's no point in fiction because it's based on the fantasies (rather than the creative imaginations) of fiction writers, then you must think that it's unnecessary; ergo, superfluous is a better word choice.

If you use redundant, however, you probably mean either that there are too many fiction writers (in which case only some fiction writers are redundant), or that fiction itself is unnecessary because we all live our own "real" everyday lives and don't need to read the details of someone else's phantasmagoric everyday life (in which case fiction itself -- what fiction writers create -- is unnecessary).

I find your use of redundant strange, non-idiomatic, and unnatural; superfluous sounds right to my ears.