If he's 200 NM east of Atlantic City he's operating VFR in a National Defense Operating Area. They're trying to figure out who he is. He's still outside the US ADIZ, but if he were to make a turn toward U.S. airspace without identifying himself he might get to see an F-18 Hornet up close!
This confuses me (though it seems to agree with the audio). If he was 200 nm east of ACY, then he was WAY outside the ADIZ, which I generally think are at like 15m. It looks like he'd be between the NENDA and LARGE fixes, which is way outside the ADIZ, and even relatively far from the W areas. Also, they said he was heading ~50 degrees, which is pointed away.
I don't have any experience with intl flights, so I'm truly curious...