Personally, I'm of the opinion that this says less about the blogosphere and more about how shitty Obama's press secretary is. I'm amazed he's still on, I thought he was a pompous idiot the first time I saw him.
I'm also not surprised how much the blogosphere is left leaning. It's been my own experience that the Dem's are much further ahead on the uptake as far as embracing the Internet and all that whereas the Right has only recently begun to step up and assert themselves on the web. If memory serves, Obama was very hip and popular with the younger, techno-savvy crowd so I'm not at all surprised that he has a small army of bloggers supporting him.