The main reason people don't trust the "MSM" is because there has been a very successful, long-running, right-wing campaign to erode public trust in media, going at least as far back as Rush Limbaugh in the 90s. You are an example of how well that campaign has worked. Never mind that most of the people who tell you not to trust the MSM are lying to you way more than anyone in the MSM is. I mean, who would you actually consider a trusted news source at this point?
Also, CNN is not a "mouthpiece for the left" - you should try talking to an actual leftist about CNN and see how they react when you tell them that, lol. To the extent CNN is a mouthpiece for anyone, it would probably be most accurate to say they are a mouthpiece for the political establishment, spanning both sides of the aisle but largely centrist overall.