So, if there were two sides in a story and, say, an investgative journalist unearthed and presented some fact that resolved the matter, then you might loosely say that journalist was an arbiter of truth on behalf of the public by simply presenting the fact. This was true even as little as a decade ago. And it might have even been considered pedantic to distinguish between journalist as presenter or arbiter.
But this is no longer the case. We are now in an age where people actively refute facts and deny reality itself. They sell the idea that the audience can choose what's true. So when the same journalist presents a fact, he is then accused of bias and becomes a part of the story. Thus, even simple truths have now become debatable to the point that merely presenting them can be cast as arbitration, as if these facts are subjective, thus there is still some matter to be decided.
Journalism as a field maybe can help us arrive at some truths eventually, but it's an iterative process of correction and evolving understanding that never ends. However, individual journalists being arbiters of the truth is just not what part of their job description. How could it be? They cannot collect all the facts, and even if they could, they couldn't report them all to the public because there are too many. So by definition journalists have to decide which stories to pursue and which facts to report, and also how to report them. You can say they should do so in as unbiased a way as possible, and I agree, but the very nature of their job involves making biased decisions.
Also, not all journalists are reporters, just as not all programmers are webdevs. There are all kinds of journalists including editors, curatorial journalists, investigative journalists, opinion columnists, photojournalists etc. Yes straight facts are nice, but I also need some analysis to help me form a nuanced opinion. A fact can tell you something, but it won't lead you to all the implications of that thing.
I think photojournalism is a great example of what I'm talking about. On its face, a photograph is a straight fact. It's a picture of a thing that happened. But the framing, composition, and editing of a photograph essentially encodes a bias, and can equally obscure or reveal the truth. And that's a good thing IMO, I want to see through the photojournalist's perspective when I look at their work. But it's still just one perspective, so I realize it may not be the truth. Recognizing that bias exists, all people have it, and to some degree it always comes through in their work, is part of finding the truth.