The Haunted Workplace: Spectral Capitalism and Dead Labor

So he seems to be saying more that you can’t reach for the “reality” behind the text because there is nothing but the text. But I have read it before as there is nothing which can be disavowed or excluded. The physical context of the text, the book, the sales process, the book reading, the glitches in digitization, the marginalia in physical copies, the supposed expert opinion in the intro contextualizing the text as if standing outside it even though it’s in the same covers, the illustration, the little slip of paper inside from quality control, heck even a note someone slipped inside. Nothing excluded, nothing disavowed and any disavowal of the text treated as just part of the whole of the text.
A little further on
“What we have tried to show by following the guiding line of the “dangerous supplement,” is that in what one calls the real life of these existences “of flesh and bone,” beyond and behind what one believes can be circumscribed as Rousseau’s text, there has never been anything but writing; there has never been anything but supplements, substitutive significations which could only emerge in a chain of differential references, the “real” supervening, and adding itself only by taking on meaning from a trace and from an appeal to the supplement, etc.”
“And that is neither because Jean-Jacques’ life, or the existence of Mamma or Thérèse themselves, is not of interest to us in the first place, nor because we have access to their so-called “real” existence only in the text and we have neither any means of altering this, nor any right to neglect this limitation.”
“Yet if reading must not be content with doubling the text, it cannot legitimately transgress the text toward something other than it, toward a referent (a reality that is metaphysical, historical, psychobiographical, etc.) or toward a signified outside the text whose content could take place, could have taken place outside of the language [langue], that is to say, in the sense that we give here to that word, outside of writing in general. That is why the methodological considerations that we risk applying here to an example are closely dependent on general propositions that we have elaborated above; as regards the absence of the referent or the transcendental signified. There is nothing outside of the text [there is no outside-text; il n’y a pas de hors-texte].”
Have I been misreading Derrida’s “There is nothing outside of the text”?
I’ve taken it to mean that when you pick up a text like a book or something and it has a series of prologues and a weird cover and an appendix and index and author bio and so on — all that stuff is inside of the text and fair game for interpretation.
But I wonder if I got it wrong. Long quote follows for context.