Professors = Ninjas?

PhD comics has an interesting comparison chart mapping out the similarities between Professors and Ninjas. Interestingly, I know quite a large number of graduate students who really like Pirates. Everybody knows pirates and ninjas do not get along. I feel like there is some kind of deeper truth here, but it is eluding me. I will have to ponder this further...

Pirates	Grad Students
Drink A lot	Drink A lot
Are often disheveled	Are often disheveled
Rarely leave the ship	Rarely leave the lab
Pillage Villages	Pillage the Free Food
Are Rebels	Want to Rebel