The book Critical Thinking Strategies For Success compares what it calls "sophistic thinking" with "strong sense critical thinking". The former is when there are doctrines and everyone nods their head yes to anything that supports those doctrines.
Recently I attended AgileDC 2013, and I noted that there was a talk by someone who I know to be incompetent and who does not know what he is talking about: in fact, he was fired from his last company for that reason; yet he was presenting at AgileDC and he has a large following in the community. That community does not know, however, that in real world situations, this person cannot perform because his knowledge does not extend any deeper than platitudes. He does not have enough real world experience to turn the platitudes into action.
Another person speaking at the conference laid out an approach that I know for a fact is not the approach used in the organization in which that person works, yet this approach was presented as a cornerstone approach. Again, after sufficient platitudes, all the heads nodded yes. More sophistry.
We are not doing enough critical thinking in the agile community. We need to be skeptical. Just because someone says something at a conference does not make it so, and where is the proof that they actually did what they say they did? Unlike scientific conferences, agile conferences are practitioner conferences, and the work presented is not research that has been replicated under controlled conditions, and there is no standard of ethics that is being enforced to ensure that people are held accountable by their respective organizations for presenting accurately. In fact, there is plenty of incentive to spin things because it enhances the careers of the presenters and the reputations of their organizations sponsoring those presenters. AgileDC - and most practitioner conferences - are more marketing than they are reality and we have to keep that in mind.
These conferences are still valuable though. There are lots of good ideas that are shared: we just need to be skeptical because some bad ideas can be made to sound viable when they are not. There is networking that happens at agile conferences, and that is always worthwhile. But don't believe something just because it was presented at an agile conference. Practice critical thinking.