Your argument implies some sort of authority in news reporting. My personal feeling is that this is precisely what is wrong with today's news reporting (specifically in the United States). It is their job to communicate what occurred. That's it. They should not assert some sort of authority to tell you how you should feel about it.
Quick example: "Prosecutors allege that the defendant robbed the liquor store. They cite a, b, and c as evidence." "Defendant claims the police are framing him and have planted evidence."
That isn't treating both arguments as equal. It's simply stating what occurred. You can verify that both things were said. It will never be perfect, of course, but I think they should adhere as closely to this as possible.
Edit: Meant to add that in my world the climate denier would have never been given air time, because it's been verified false. I think we are somewhat pointing out the same problem from two different views.
I understand and appreciate your point. That is why I used the term verifiable facts. If you can verify that claim X is false, (such as Trump's claim of a rigged election, which have repeatedly been verified to be false) then by all means, report it as such. That is not taking a side. That's reporting. At least, that's how I see it.
I disagree completely with the part about news media should choose a side. That is exactly what they shouldn't do. Report verifiable facts, without opinion. That's the only way news media should be, in my opinion.
Two things can be true.....