One of the more dangerous players in contemporary discourse -- or at least one of the types that makes me the most nervous, anyway -- are people who are trained as journalists, who know the forms of the genre, but now are working consciously and intentionally as advocates.
Adam Kredo -- he of Kamala Harris' pot-gate -- is one example. Before joining the Washington Free Beacon, he was a relatively well-respected "neutral" journalist working for the Washington Jewish Week. Now, nobody confuses what he does for the Beacon as dispassionate journalism (except maybe Kredo, who claimed -- apparently with a straight face -- that at the Beacon he remains a straight news reporter who is "not in the opinion biz"). Nonetheless, there's little question that Kredo is more effective as a purveyor of partisan hit pieces precisely because he knows how to write an article in a way that follows journalistic conventions. Get quotes from alternative sources, ask subjects for comments (that they're damned if they do and damned if they don't is a bonus), do much of the heavy narrative lifting not by direct accusation but in terms of presuppositions and framing -- it works in a way that more direct propaganda doesn't. I suspect the "news-ier" side of Fox News (not Tucker Carlson or Sean Hannity, but the parts that present themselves as straight coverage) fits this mold too.
On the other side of the street, one can see similar characteristics at Jewish Currents. Again, many of the people writing for Currents have clear talent as journalists, and their stories track journalistic conventions. They aren't obvious agitprop. But they're great examples of how, if you know what you're doing as a journalist, you know how to push every convention to the limits of its tolerance band in a way that gets you to something pretty close to agitprop while still looking on face like a regular investigation. If every choice of framing is meant to accentuate one side's story, if every presupposition of the relevant political climate or social atmosphere reaffirms a particular point of view, if every inference or interpretation is just a little credulous to the right people and cynical to the wrong ones, the result is an article in which all the constituent elements are defensible as fair but the net result is intentionally one-sided (their piece on Ritchie Torres I think works as a decent example of what I mean).
I've sometimes said that the "evil" version of me would make a good press secretary, because I think I'd be very good at spinning effectively. This is a version of that -- if you're a journalist, you know how the narrative machine works, and knowing how it works you also know how to break the machine. And as parts of a political toolkit this is very effective; arguably even necessary, even as it is also intentionally manipulative and kind of hackish. The reason "evil" me is a Press Secretary rather than actual me is that in real life I don't have the stomach for that sort of work. Which is not the same thing as saying that either I or the people I admire are perfectly virtuous or fair-minded in how we relate to our own interlocutors. We have times our biases shine through too. But there is, I submit, a difference between unknowingly being swayed by one's personal biases, or even a temporary lapse acknowledged as a wrong, and knowingly and self-consciously trying to align one's work product with one's biases to the maximum extent possible.
In any event, I suspect the people who do this are in fact decently self-conscious about what they're doing -- they don't (contra Kredo) actually think they're not engaged in opinion; they're relatively open about their agenda. Press them, and they might say something like "all news coverage has a political agenda behind it; the difference is that we are self-conscious about it, whereas the people who think they're doing straight news are more likely to be unconsciously parroting orthodox Pablum without recognizing that's a view too." And I have some sympathy for that critique, actually. We all could stand to be more reflective on what our biases and presuppositions are. But I also think there is a difference between actually trying to understand issues on their own terms and be fair to subjects one is covering, versus just going through the motions of it because "hey, everyone has an agenda right?" Such is the curse of many liberal values (objectivity, neutrality, even-handedness, etc.): they're simultaneously impossible to achieve, and yet things are so much worse when people stop even trying to achieve them.
Demystifying the very much non-neutral "mainstream" coverage norms need not necessarily take the form of "replicating those norms, but intentionally and in service of a different political program." But in practice, it often does, and the result is I think work product that is very slick, very effective for its chosen audience, and very dangerous for the project of fair-minded discourse.