What looks like a platitude today was not so at the MLA circa 1970. The idea of a rigorous theory of textuality was itself something of an affront to those who believed they knew what kind of object they were studying. Among other things, the idea of the text was upsetting to those in literary studies who knew there was a bright fine line between philosophy and literature, lit and crit, etc. The philosophers were, of course, doing more important things than mere literature, etc. Bringing maps, architecture, history, travel diaries, all kinds of flotsam and jetsam to bear in reading the heretofore privileged literary artefact wasn't altogether new, but JD's work--at the time, inseparable from Foucault's--gave that effort a kind of language and respectability it hadn't had before.
Christian