"The defensive writing style also encourages another sort of ugliness, which is that “avoiding saying something wrong” becomes a primary focus of the writing, rather than communicating or exploring ideas which the author might himself be unsure of."
One thing that's great about Gwern Branwen's writing is that Gwern's essays are accompanied by a "belief tag". That tag gives the ability to say "This essay is exploratory; I don't have a high degree of confidence that it's canonically true." Details here: http://www.gwern.net/About#belief-tags
Having the option to dissociate ideas from one's person can give a lot of freedom to put contrarian ideas out there and spark debate in search of the Truth without fearing personal attack. Indeed, one of the things that I consider to make a healthy company culture is that ideas can be criticized without the people behind the ideas feeling criticized themselves.