I really wouldn't have a problem with CNN if they were just honest at this point about who and what they are. I mean, MSNBC is way left. But they aren't shy about it. They embrace it. It's part of their identity.
CNN is still trying to pass itself off as an impartial source of "news", and a lot of people still view it that way. Which means those people are consuming left-wing analysis and commentary as if it's fact.