Personally, I think a lot of the bad writing of the pomos in English comes from two sources, one innocuous and one not.
1) Pomo is of French origin, and many of its principle figures were/are French. The books in English are a translation. Moreover, like Aristotle and Heidegger, the pomos do a lot of wordplay. In French. So, you get the same goofiness in the translated works of Derrida and Foucault as you do in those of Aristotle and Heidegger, because the translators are attempting to render the internal logic of another language.
2) Anglophone pomos imitate the bad translations from French. It would be as if a bunch of Chinese fans of Joyce were trying to write like Chinese translations of Ulysses.