The article does state that the referenced study may be seen as endorsement of this new shiny approach without clear analysis of the problem. What is true, in my experience, is that Agile is poorly implemented across the board. Sprints are just biweekly massive status updates and no developer talks to the customer/stakeholder directly. So, criticism of implementation should not have been underrated in the article.
That said, in the referenced study, they are calling some ad hoc development practices without requirements "agile", because they feel like calling it that, and then blaming the authors of Agile Manifesto for not delivering on their promise. Clearly, today, a lot of software management malpractices are called "Agile" and then the fault for the failure is pointed outside of the organization. It's the management's fault, not the Agile methodology.
That said, in the referenced study, they are calling some ad hoc development practices without requirements "agile", because they feel like calling it that, and then blaming the authors of Agile Manifesto for not delivering on their promise. Clearly, today, a lot of software management malpractices are called "Agile" and then the fault for the failure is pointed outside of the organization. It's the management's fault, not the Agile methodology.