All of these things are true, but none is a reason why one shouldn't take the substance of Derrida's work seriously. I find it very useful to study right-wingers, especially smart ones like Heidegger. And the difference in the French and American contexts is very interesting; why do you think his popularity dwindled in France? When I spent a short time in the French university system it seemed to me that the Enlightenment model of scholarship had been totally restored, sometimes incorporating "post-structuralists" (this term does not exist in France) into its reactionary model, but never taking seriously the implications of their work for the conduct of intellectuals. In the United States, appropriating Derrida led to apolitical scholarship, but it seems that studying Derrida can help us answer an important question: what is it about the American intellectual zeal against totalizing theories that leads to political apathy?