He has summerized very well why Agile can be applied to others domains, and beyond the IT one, giving some real examples in successfull firms.
Then the extension of Agile from management in firms to politics was indeed pretty obvious : the Manifesto for Agile Development of Democracy was born.
Agile is about accepting a new way of thinking. If you are already a really convinced Agile practitioner, then you will have no problem to understand and accept the MDAD principles. MDAD is also a kind of a test of your maturity in Agile : are you ready in your mind to accept this new way of thinking, really ?