As I see it, there were two problems:
(1) Were the analyses all that precise in the first place? Take de Man's famous distinction between grammar and rhetoric. What he meant by the "grammatical" reading of a rhetorical question was something like a literal, non-rhetorical meaning. But in what sense is this "grammatical"? How is the grammatical a synonym for the literal? (Don't answer that question!) Doesn't the rhetorical question have the same grammatical structure however it is interpreted? I don't find it all that interesting to read Yeats's rhetorical question, "How can we tell the dancer from the dance?" as though it were a real question: "Tell me, how can you tell the dancer from the dance?" If this is the most famous deconstruction of a poem, I want my money back.
(2) Insofar as the ideological tendency of deconstruction, at least in the US academy, was to encourage a kind of interpretive freedom, this appeal to freedom undermined the appeal of precision. Or else the vaunted precision of the interpretation ended up limiting interpretation to a binary choice. The idea was that the interpreter would be eternally caught in an aporia between two conflicting readings, but these two readings turned out to be very determinate.
If the text is anything you want it to be, however, then there seems little point in insisting on the precision of the method. In other words, the demand for technical precision conflicts with the appeal of hermeneutic anarchy.
People who liked deconstruction, I suspect, were seduced by the possibility of having it both ways, having the professional expertise of the close reader and the existential freedom of the textual anarchist.
There's a dialogue between Derrida and some critics (Anne McClintock and Rob Nixon, two graduate students at the time) in Critical Inquiry (Autumn 1985 and some subsequent material in Autumn 1986). He had said, basically "Let Apartheid be the last word." His critics interpreted him as saying that Apartheid WAS the last word. He came back and pointed out that he hadn't read the subjunctive right. It was "soit" and not "est," so to speak. He denounced their rhetorical incompetence, and rightly so. But here there is no textual aporia: Derrida is correct and his critics are not.
If you had paid attention to the context and the modeof my text, you would not have fallen into the enormous blunder that led you to take a prescriptive utterance for a descriptive (theoretical and constative) one. You write for example (and I warned you that I was going to cite you often): "Because he views apartheid as a 'unique appellation,' Derrida has little to say about the politically persuasive function that successive racist lexicons have served in South Africa" (p. 141). But I never considered (or "viewed") apartheid as a "unique appellation." I wrote something altogether different, and it is even the first sentence of my text: "Apartheid-que cela reste le nom desormais, l'unique appellation au monde pour le dernier des racismes. Qu'il le demeure mais que vienne un jour . . . , " which Peggy Kamuf translates in the most rigorous fashion: "APARTHEID-may that remain ... May it thus remain, but may a day come... " (p. 291). This translation is faithful because it respects (something you either could not or would not do) the grammatical, rhetorical, and pragmatic specificity of the utterance.
So Derrida could appeal to precision, to specificity, but he could not do so and at the same time advocate for interpretive anarchy. That was never his game anyway. Derrida was not some advocate of let-it-all-hang out interpretation.