You can thank Joe Costello for that. He put WRNO on the air in New Orleans with an alleged "target area" of Europe - beamed right up the Atlantic coast. More recently Al Weiner did the reverse with WBCQ - built it in Maine beaming to Latin America. In both cases they had excellent coverage of the large population centers of the USA.

"Legally" they cannot target a domestic audiance, but it certainly doesn't stop them from doing exactly that.

The bible-thumpers you mention above are mostly time-brokered; if you want to get on the air you record a program, buy an hour on their transmitter, and they'll put you on no questions asked.