[WS:] I think his main thing was to take a jab on the neoclassical economic theory and also Marxism inasmuch as they treat their social engineering vision as a description of empirical reality. In other words, he is arguing that what these guys say is how they want people to conduct transactions rather than describing historical reality - although they want everyone else to believe that the latter is the case. Graeber also comments that Marx's intention was to critique bourgeois economic theory by pointing its internal contradictions rather than using it to develop a blueprint for real life economic system - a point raised by others, including myself.
A logical conclusion of his argument - which he does not explicitly spell out afaict - is that there is no such a thing as capitalism, only its idealized (or demonized) image painted by its promoters (or detractors). What we have instead is human interactions that under certain conditions can degenerate into impersonal exploitation. He identifies this condition as the ability to "abstract" human individuals from their social connections and view them only as quantities being exchanged. So far, so good. Where he falls short, however, is to identify specific historical/political conditions that make this abstraction process possible. He does a little bit of it in his discussion of slavery in West Africa but he falls way short in his discussion of Europe and China.
-- Wojtek
"An anarchist is a neoliberal without money."