It's really difficult for me to see what Foucault you're reading to support this Foucault vs materialism thesis. Or, rather, I don't see why you've chosen to read him this way, which you would have to admit to be highly selective.
In the post via Doug you appear to concede this isn't really about Foucault but about some ways in which Foucault has been used. I just don't know why you don't criticise the people responsible for this *use* then. Surely this manouevre is both sloppy scholarship and politically pointless.
Materially yours, Catherine