No-Fly List Diversions

Why do the Homeland Security people divert arriving international flights from their scheduled destinations to Bangor, Maine?

It happens every few weeks. A flight leaves Europe for, say New York. When it's halfway across the ocean, the people checking the passenger list notice a name matches one on the No-Fly list. So they order the flight diverted to Bangor at great inconvenience to all those people headed for New York so they can talk to the person whose name matches one on the list.

So why can't they talk to that passenger at the original destination?

Is it a manifestation of the same desire to demonstrate power that causes some police agencies to block an entire freeway for several hours while they investigate a two-car accident in one lane?