That may be mostly true...
but I find the characterization of Obama as a leftie pretty suspect. On the one hand he pushes for these overtly liberal programs like Health Reform but then runs as close to the middle ground on that as it is possible to go without actually abandoning the whole thing. He pushes the stimulus through but then a significant hunk of that is just tax cuts and another hunk aids corporate interests. Then on the war and the military there isn't a fag paper to slip between him and the neocons-the talk may be different but the results are all the same. The whole Wall Street bailout wouldn't have gone down any differently unless Paul was in charge-no GOP president would have stood up to them in the pinch or done anything dramatically different.
He is a leftie from a perch out on the far right but to liberals he is just one more centrist like Clinton. It's his greatest weakness-you have to choose sides in politics and he doesn't and winds up looking bad to everyone. You may be too young to really have a feel for what true liberal Democrat at the Presidential level looks like-but I'll tell you they didn't look like Obama.
But, that being said I think you are mostly correct about the constituency of the press bias on a numbers basis-I would hesitate to take the same line on an influence basis however. But, I'm not of the school of thought that you can have an unbiased press. It just isn't possible.