Pardon my ignorance in asking this stupid question:
Isn't the mainstream position among decision theorists that defect is the optimal strategy in a one-shot prisoner's dilemma game? Sure, we can say something like "a TDT-agent will cooperate with another TDT-agent." But even a TDT-agent will defect if it doesn't know the identity of the counter-party. And TDT isn't completely formalized yet, right?
In short, I'm not sure of the value of snarking a popularizer of decision theory for using the word "rationality" differently than this community uses the word, particularly when our usage is (unfortunately) not the consensus definition in the relevant field.
Depending on the payoff scale, a TDT agent will cooperate if it believes that the other agent has some (high enough) chance of being a TDT agent. In other words, raise the sanity waterline high enough, and TDT cooperates.
TDT / superrationality will defect probabilistically given a high enough payoff for defection, even against a known-TDT agent.
In short: TDT and superrationality theories aren't as simple as some here make them out to be, and the one-shot prisoner's dilemma has hidden depths for smart players.
It's a brilliant idea: a lecture by a cool modern thinker, illustrated by word-by-word doodles on a whiteboard. Excellent at pulling you along the train of thought and absolutely disallowing boredom.
The lectures' content is pretty great too, although there's a definite left-wing, populist bent that's exploting today's post-crisis hot button issues (they got Zizek, for god's sake) - some might not like it. Regardless, it's all very amusing and enlightening. Been linked to before in a comment or to, but it deserves a headline.
You can start here: http://www.youtube.com/watch?v=dFs9WO2B8uI&feature=relmfu (But they're all worth watching!)