“Why do we have to rely on mostly left-wing British newspapers to find out what Mr. Obama is up to? “
The American press has a sense of ownership and buy-in on the Obama administration. Obama is literally their creation. Even if a reporter found the story (it would have to hunt down the reporter and show him a body in the trunk)and he wrote it, the editor would recognize the damage it would do to the liberal agenda and kill it.
As an example of how agenda editing works, I was writing business puff pieces for my local paper, “The Tallahassee Democrat.” (Until I got the job, I actually thought it was the Democratic Party’s newspaper.) The business owner would pay the paper to have me write the piece. I always looked for an interesting angle and made the article as informative and useful as possible. Many times the editor, a Subaru-driving former hippy, would edit out the most useful and informative bits. After a particularly egregious editing I asked her why she’d taken the material out. Wafting her hand and with a sneer she said, “Oh, it was just too pro-business.”
That's the one side, they want to protect their guy.
On the other side, they hate normal American. They hate conservatives, Republicans (God knows why in this case), Christians, the free market, traditional morality, patriotism and ordinary people, who want to do for themselves. Can't have that, they think the wrong thoughts and make the wrong decisions.
Their hatred is their prime motivator. The won't publish anything that they see will help they people they hate.
In fact, this one sentence is all you need to know about media bias:
The won't publish anything that they believe will help they people they hate.