The National Broadcasting and Telecommunication Commission (NBTC) on Friday punished a TV operator for airing Dexter, an American drama series about a serial killer, because of its “inappropriate” content.    Natee Sukonrat, Chair of the NBTC, said the drama violates Article 37 of the 2008 Broadcasting Act which prohibits the TV operators from airing content deemed a threat to security, a breach of public morality or public order, or obscenity.