Dateline’s executive producer David Corvo prefers to see the change as a setting aside of older journalistic conventions to focus on new kinds of issues. The “Predator” series, he says, is just another form of enterprise journalism, one suited to the Internet age. But the distinction between enterprise and entertainment can be a difficult one. Dateline hasn’t so much covered a story as created one. In the process it has further compromised the barrier between reporters and cops that is central to the mission of journalism. If humiliating perverts and needlessly terrifying parents is the best use that newsmagazines can make of hours of primetime television, then perhaps they should be allowed to die and the time given over to the blood sport of reality programming. At least no one would dare to call it news.