He is very emotional when reporting... but in 03/04 he was a big Bush cheerleader like everyone else. He's become the only voice in mainstream media to actually call out the White House for - drum roll please - using fear tactics on Americans.
Everytime there's a terror warning, Olbermann points out that 1-2 days earlier, the white house was hit with a scandal. It's called the "nexus of terror and politics". youtube it. Something like 20 instances - every terror alert we've had, is coincidentally very politically beneficial for the white house. Can't get a bill passed - terror alert - you get your bill. Big story making AG look bad - boom - another alert to take the headlines.
Olbermann might be a whiner, he might be overly emotional, but he does call out the use of fear to get their way.