The most common defense for this sort of behaviour -- which was more manifest than ever at the president's most recent press conference -- is that they HAVE to do what they're told, play along with the rules, and stay away from the hardball questions, because if they don't, they'll lose their access to the White House altogether.
Aside from the inherent problems with defending your behavior by saying you have to do as you're told, I have three problems with this excuse, which reeks more than faintly of bullshit.
1. It defers all responsibility away from the reporters. I mean, if you think about it, it's pretty unworkable, right? Let's say you work for NBC ask the President a tough question, so he bans you from press conferences. Why can't your replacement ask equally tough questions? After all, the president isn't going to just stop talking to the press altogether, is he? If the reporters agree collectively to show a little goddamn spine, this wouldn't be an issue. As a great man once said, people don't do whatever they want; they do what you let them do.
2. Related to my first objection: I would say it's news that the president bans reporters who ask him hard questions. Why not make that an issue? Why not shame the administration into ending the practice? Why not report: "PRESIDENT HAS LIST OF BANNED REPORTERS; Refuses To Allow Questioning from Certain Media Outlets". I'd say even in the current political climate, that would raise a few eyebrows. It certainly doesn't make the administration look good.
3. Finally, what's the point of even having reporters if they aren't going to do their jobs? They say "we have to ask the questions they allow, or we won't be able to ask any questions at all." So what? Is it somehow better to have a worthless media presence at press conferences than no media presence at all? Why should I care if they get banned, if they aren't doing their job when they're not banned? Why have reporters at all if they defer their responsibility?
Anyway, good article about it here. The 'drop them out of an airplane' stuff is a bit over the top (though amusingly so), but it nicely makes the point that if the press isn't doing its job, then what are we paying them for?
Meanwhile, in case you were worried that Americans aren't coming off as arrogant, bullying and hegemonic ENOUGH, here's some good news: Knife-wielding US troops storm a protest camp in England.