The War on Thai children and Bayes' Theorem

Last year Sailer commented on an article from Slate's Shankar Vedantam who wrote this curious paragraph

"People in Thailand will associate white American tourists with pedophilia even though many more acts of pedophilia are committed by Thais. But white Americans are a minority in Thailand, as are acts of pedophilia. So you will hear Thai people shout until they are blue in the face about individual anecdotes showing white Americans who are pedophiles. (The same is true of gay men and pedophilia in the United States.) "

Thais may know Bayes' theorem and that the facts "that many more acts of pedophilia are committed by Thais" and "Americans are minority in Thailand" do not imply that nationality is irrelevant to gauging the risk of bad touching.  Let P(BT|W) and P(BT|T) be the probability of being a bad toucher given that an individual is white or Thai respectively.  Bayes' theorem gives 

and

where P(W|BT)  and P(T|BT) are the probabilities of being white or Thai respectively given that you are a bad toucher and P(T) and P(W) are the probabilities of being white and Thai.  Using basic algebra you get 

So Thai children should be more wary of whites than Thais if the proportion of whites among bad touchers is higher than their proportion in the general population.  I do not know if this is true but it seems reasonable.  So Thais may be perfectly rationale by stereotyping whites and by ignoring this possibility Shankar Vedantam appears to be either innumerate or a NAMBLA shill. 

Neven Sesardic gives a more academic treatment of Bayes rule and rational stereotyping in Making Sense of Heritability (page 218) but his example is not as much fun.