Greenwald makes much of the question, "How could multiple sources get the date wrong in the same way?"

My bet is this was a setup. Let's come back in a week and see if I'm right.

[edit]

And now that I've gone back and read the rest ...

He's saying that the MSM (he might as well use the acronym, that article could have been an opinion piece on Fox) consistently err in the same direction. What I'm saying is that this wasn't a Democratic actor trying to spread a story to discredit Trump and the media erring in not verifying it, as Greenwald says. This was Project Veritas or someone like them trying to discredit the MSM by feeding them something juicy yet easily disproved.

As for his actual claim - that the media consistently err in the direction of suspecting Russia of all kinds of things - I think there's a non-zero chance that Russia is actually doing far more things than we've heard of, that a solid majority of what makes the national news outlets is likely true, and that the stories that are "debunked" are more often errors of excessive credulity than intentional fabrication. As opposed to the steady stream of transparent lies coming from the Trump administration for the last year, and Fox for the last decade.