No, they do things that are not mistakes. It's OK. I don't expect you to believe it.
Sure, of course the "MSMs" sometimes deliberately report bad information, or likely far more often, pass along misleading or false information fed to them from their 'source' in government or industry or elsewhere. But that's not saying anything other than news organizations are run by people, who aren't always honest. Well, that's true of any organization or group you can name - governments, for profit businesses from the smallest to Fortune 500, non-profits of every size, shape and purpose including churches, of every religion.
So now what? If you need to know or care about the "news" then what do you do with this knowledge that every news organization that has ever existed, and members of every other major organization on this planet for all time, has likely done things that are not mistakes to mislead you?
In my experience, it's much safer to trust the "MSMs" because they have more to lose by lying to you, and losing your trust, than any other source. And there are 10s of thousands of reporters and other employees who cycle in and out of those news orgs over a decade or so, and how many stories are there of reporters fabricating news? There are a few that we know about because when caught it is a MAJOR scandal. But there are too many people involved for that kind of thing to be common practice for those scandals not to erupt every few months.
So given that is the rational approach, that's what I do. If the NYT reports that WH source Jack (or a senior unnamed official) said something, my best bet as a consumer of information is to trust that did happen. Now I can read that and be skeptical if that source isn't named and the information is more like gossip than hard facts, but then my next best bet is to try to figure out why a WH source is leaking that kind of damaging information that I suspect might be misleading or worse. IMO, the absolute dumbest approach is to assume NYT is lying, and just fabricated that whole story. If we could prove it, I'd give you good odds, 100-1 or better, and bet against that being the case all day, every day. Pick your favorite major conservative outlet and I'd say the same thing.