A hypothetical in which 50% of the population is terrorists doesn’t sound particularly relevant to the real world. And if the fraction of the population which is purple people is less than 50% (let’s call it p) learning that somebody is a purple person doesn’t only give 1 bit of information, it gives -log2(p) bits, which in order for p to be remotely near the fraction of terrorists in the real world would have to be at least a dozen, I guess.
A hypothetical in which 50% of the population is terrorists doesn’t sound particularly relevant to the real world. And if the fraction of the population which is purple people is less than 50% (let’s call it p) learning that somebody is a purple person doesn’t only give 1 bit of information, it gives -log2(p) bits, which in order for p to be remotely near the fraction of terrorists in the real world would have to be at least a dozen, I guess.