I can't find out how this data collection got under way, but I would bet that the architects of this massive waste of time are not professionals. It's one of those grand schemes that inspire ignorant people but make actual experts impatient. How many terrorists could there be? A hundred? Two hundred? Does it make sense to listen in on a trillion phone calls in order to catch them? Probably the confident rejoinder is "data mining", which was so huge a few years ago. The idea is you can collect information from all sorts of sources by looking for patterns and assemble it into something useful. But that's good for finding out that people who buy beer also prefer Cheetos to jelly beans and things like that.

Of course if the purpose is just to spy on certain individuals, then pretending that it's really a completely random universal programme is a good idea.