Mark Nottingham's own words answer better than I do, and you should read the RFC. It's not quite one way or the other. It's kind of a "well decentralization is great and yeah centralization is bad but how realistic is decentralizing things anyway and when?"
But Mark's own words handle it better
From the RFC:
> This document argues that, while decentralized technical standards may be necessary to avoid centralization of Internet functions, they are not sufficient to achieve that goal because centralization is often caused by non-technical factors outside the control of standards bodies. As a result, standards bodies should not fixate on preventing all forms of centralization; instead, they should take steps to ensure that the specifications they produce enable decentralized operation.