I think the original writer of the poster might have accidentally inserted the double negative ("not" and "exclusive") because the original writer is not a grammar nerd. I'd say that generally compelling writing and correctness might be mutually exclusive -- but only to those people who have a sense of "correctness" and care about it. When does so-called correctness really matter? Most student writing that I have to read might be technically correct but tedious and over-stated. I believe that generally the more you perfect the form, the more you perfect the content -- but perfection is a point on a continuum with unclear end points.
Don't you find that style often supersedes text book grammatical correctness? Form conveys content that is sometimes additive to the words themselves; subtext, perhaps, that can only be conveyed through the author's unique description. This, however, is often not given over to putting one's commas, periods, conjunctions, and prepositions in the pre-agreed upon places. (And notice the Oxford comma, which I am quite fond of! [Or, "of which I am quite fond," if we're being huge nerds.])
We can't hold on too firmly to any notion of textbook grammatical correctness. Whose textbook? Whose grammar? I would ignore any rule of grammar if the style moves me to connect with the author. So-called correct grammar often leads us into contortions, such as "of which I am quite fond." I believe there is a movement afoot to let the preposition rest at the end of many sentences. By the way, if you are a writer of research papers, are you now allowed to use first person or do academic journals still force you to contort into a third person voice? There is a movement afoot to reclaim the first person.