One thing you guys are forgetting...
if you had watched MSNBC from 2007 to 2008, you had seen Hilary and Edwards pretty much expose Obama as inexperienced.
Every single time Hilary got on tv, she pointed out his lack of experience. Every time.
So while yes, nbc pretty much rooted for Obama against Mccain - There were two years of Obama getting slammed from every direction in the left, looking clueless in debates, etc. For example, remember her absolutely PWNING him when he agreed to meet with foreign leaders without pre-conditions in his first year? holy crap, it was nonstop for a week - how could he answer so stupidly.
So from the inexperience, to the terrorist friends, etc - The Dem candidates did punk him with it for 2 years to lib voters. Now you know - and knowing is half the battle.. GI JOEEEEEE