I typically don't like to read into the motivations of articles (or people's actions for that matter) and I take their words as an independent object. Given the article has a logical flow with plenty of high quality citations, I'd say his thesis of "willpower is ill-defined" is a valid statement.

EDIT: The author is an Assistant Professor of Clinical Psychiatry at Columbia University, whether or not that affects your view of the article is your prerogative.