It’s true that they may not be experts in everything that they report on, even if it’s their niche. Eg I think Kara Swisher does a reasonably good job of representing technology related things but there’s things she says that are not really true.
However the one thing journalists do cover well and have good expertise in is current event and politics. They are closest to the sources. And thus they become pretty good at identifying BS in those narrow fields at the very least. Given that, I certainly value their “take” on what the current events portray.