Firstly, most mainstream news websites have rules and policies on showing videos coming from unknown and unvarifieable sources - especially war. The concern is that videos can be edited and doctored to make them appear to construe something else that doesn't represent the true facts.
I'm not saying this video is doctored/edited in this way, but it's a blanket policy most news orgs will keep to. Instead they will report that WikiLeaks have this video and link to them instead. Which is what is happening here.
There is a second, and somewhat sad issue here too. That video remains property and copyright of the US military, which means news organizations probably wouldn't want to redistribute it anyway as they don't have permission. News orgs have been known to republish photos and videos they don't own when there is extra-ordinary reasons but I don't know if this is enough to warrant that.
As an aside, I'm also concerned that it could get pulled from YouTube if the US military issue a DMCA notice or similar request due to national security.
Everything created by the USFG is automatically public domain, but just because something is public domain doesn't mean it can circulate freely in public.
Even stolen information cannot be enjoined from publication by the government.
In the website they say that they made a freedom of information request but later say they had to decrypt the video.
That seems to suggest that the video was not released to them under the freedom of information request and instead an encrypted original was obtained by other means not explained.
I doubt any video of recent active combat is going to be declassified and thus available under a FOIR, and if you obtain something illegally/unofficially that doesn't suddenly make it public domain.
(to be clear, I'm glad this video is out there - it is an important story being told. But IMHO the distribution status of the video is a reasonable discussion topic none the less)
http://www.washingtonpost.com/wp-dyn/content/article/2009/09...
The leak of the video is newsworthy and it will inevitably get picked up, but Wikileaks didn't document an event that anybody didn't already know about. Reuters saw the video in 2007 (and was unfortunately not allowed to copy it).
http://www.foxnews.com/politics/2010/04/05/video-appears-for...
Edit: URL
In actual fact their article seems either rushed or ass covering. There are many "they say" and "appears" in the article.
The reason is that so long as they only report fact they're quite safe. So when they say
a voice says: The transmissions says of one of the individuals: "He's got an RPG [rocket-propelled grenade]. I'm going to fire.
Then they can't be said to be inaccurate - the video does indeed include someone saying those words. The article just leaves it to the reader to decide upon its accuracy - a very safe option.
That said this video doesn't really need a 'report' so much as a pointer to its location. It speaks for itself - chilled me to the bone.