The beauty of Agile is: if you question or criticize it, you don't understand it; if it didn't work for you, you didn't apply it properly; if you applied it rigorously and it failed, you didn't have a deep understanding of it. Was it Sartre who said "it is what it is not"?
Agile is not an "it", agile is not static. Application of agile principals means guiding and improving development processes. This is not a damned if you do damned if you don't scenario. As the article suggested, you have to "inspect and adapt". If something did not work for you, then capture the results, perform a lesson's learned, and try again.
To say "apply agile methods", is to apply a nimbleness of the mind. This is where not everyone "gets it" right away. If someone suggests a paradigm shift from what you as a developer are accustomed to, you may very well fall flat on your face. But to apply agile methods means to be able to get back up and try a different approach.
