Postmodern Culture has an article on ontology and the left.

Since Heidegger and up until the mid-1980's when a deconstructive version of Marxism emerged in the works of Laclau, Mouffe, Zizek, Badiou, a.o., ontology was synonymous with Heideggerianism: "Contemporary philosophical 'ontology' is entirely dominated by the name of Heidegger," Alain Badiou correctly stated in 1988. Badiou himself, of course, will break with this tradition; yet this general identification of ontology and Heidegger allowed most leftist intellectuals at the time to dismiss the entire ontological tradition as a dangerous aberration in Western thought. As a philosophical tradition, ontology is not only suspect among leftist intellectuals. It is part of an oppressive super-structure that affirms rather than challenges the existing status quo. "In all its mutually excluding and defaming versions, ontology is apologetic," Adorno unequivocally states in 1966. For Adorno, the basic fault of ontology in general, and of Heidegger's "foundational ontology" in particular, is its essentialism, which seeks the eternal, self-identical truth underneath the flow of history.

I don't doubt that Adorno's misreading of Heidegger led the left into an ontic wilderness, but Adorno is not solely to blame here either.  ¶ 3:20 PM