I don't think the issue is whether CNN is "liberal media", but rather the very clear and obvious point they provide on this subject. The bias is just screamingly apparent.

As for CNN themselves, I'd say they are slightly less liberal than MSLBC. But, with this segment, I also imagine it's simply the number three news station trying to somehow suck some ratings off covering Number One and Number Two. They aren't involved, and contrary to what the guy says at the beginning, they so obviously want to be involved in this FOX/MSNBC/WHITE HOUSE thing. They want to be relevant and talked about. And the way they are trying to do it is by pointing out the fallacy of the White House's official statement on the subject.