Following up on my comments earlier, Greg Marx makes the good point that in Obama's case, the press had him not only on goo goo grounds, but also on hypocrisy.
I tend to think that a simple focus on hypocrisy is actually part of goo goo values, but Obama did make himself vulnerable on the related, but slightly different, grounds of breaking promises. Hypocrisy is about exposing the differences between actions and true beliefs. As such, it is a dangerous game to get into -- democracy does not thrive when people are constantly questioning motives. Broken promises, a far more objective topic, are certainly fair game for reporters, even if it's true that goo goo reporters might be drawn to that particular subject because they care far more than they should about hypocrisy.
Breaking promises isn't actually bad because it reveals that politicians aren't what they claim to be; it's bad because it tends to harm the representational relationship between constituents and their elected officials.