Why do members of Congress, nice enough in private, get tough on camera, when network journalists, presumably also nice in private, stay nice on camera?

In his new book, "Duty: Memoirs of a Secretary at War," former Secretary of State Robert Gates makes this criticism of the members of Congress:

During his tenure as Pentagon chief, Gates often found himself tempted to quit because of the adversarial treatment he received from members of Congress. He says that in private the lawmakers could be reasonable. "But when they went into an open hearing, and the little red light went on atop a television camera, it had the effect of a full moon on a werewolf," he says in an excerpt in the [Wall Street] Journal.

Here's the WSJ excerpt, in which I cannot find that quote, but there's additional text about Gates's dismay at congressional brutality. He says that at congressional hearings he'd often thought of slamming his briefing book shut and saying: "there is no son of a bitch in the world who can talk to me like that. I quit." He complains about "the consistently adversarial, even inquisition-like treatment of executive-branch officials by too many members of Congress across the political spectrum—creating a kangaroo-court environment in hearings, especially when television cameras were present."

Are television cameras to blame? Yesterday, I was talking about how inanely nonconfrontational David Gregory is on "Meet the Press." He and his fellow journalists coddle administration officials. They sit back, nod, and say "okay" and "right" as these people deliver their prepared talking points. They don't seem to understand that they need us, the audience, and we want vigorous, probing questions. They're making one another comfortable, on camera, in the manner Robert Gates describes as prevailing behind the scenes in Congress.

How can we explain this difference? Why do members of Congress, nice enough in private, get tough on camera, when network journalists, presumably also nice in private, stay nice on camera? Let me offer a few answers for your assessment:

1. To put on a good TV show, you do need to get tough on camera, and "Meet the Press" is failing as a TV show. It's ratings are way down. Maybe members of Congress should not see themselves as putting on a TV show, but they are modeling how to put on a show.

2. Members of Congress have the power to force administration officials to appear and to testify under oath, but the producers of a show like "Meet the Press" can only extend invitations, invitations that will be accepted only if the invitees think it will be to their advantage. As there are more than one show, a host needs to give the best party to entice A-list guests. The real guests that matter, of course, are the home audience, but the TV show folk must think the viewers look at the guest list to decide what to watch.

3. Members of Congress face elections, and the judgment of voters exerts more pressure than the judgment of viewers. The viewers and the voters are just the American people, but each member of Congress is answerable to his (or her) constituents, and a national TV show is trying to appeal to everyone. The member of Congress has a more focused idea of what people in his state or district are going to grill him about, and the journalists involved in a TV show think more vaguely about what will make people tune in and stick around.

4. Both the members of Congress and the journalists are supposed to feel a profound sense of responsibility for the power they exercise, but actual power to legislate is different from a power only to influence people through the force of words. You'd think this difference would create more vigor in the expression of the journalists, so why would it have the opposite effect? The easiest inference is that the aim of the journalists is to lull the people.