Holy cow -- do we really need this sort of conspircy thinking? What is the suggestion here, that Seymour Hersh is a CIA agent? (By the way, its Hersh, not Hersch).
Look, if you read between the lines, it is clear that Hersh's source for this story are the families of the soldiers being sentenced. The families think their kids are being rail-roaded for something ordered on from high -- so, they've given over photos and documents to various media outlets, including Hersh.
Now, it is true that Hersh does rely on government sources, usually mid-level CIA agents and military bureacrats. But that's because these are the people who know where the bodies are buried, and often have a greivance against the cover-ups of those on high.
Scott Sherman has a nice quote on this in a profile he did of Hersh for the Columbia Journalism Review:
"I don't go around getting my stories from nice old Lefties or the Weathermen or the America-with-a-k boys," he told Rolling Stone in 1975. "I get them from good old-fashioned constitutionalists. I learned a long time ago that you can't go around making judgments on the basis of people's politics. The essential thing is: Do they have integrity or not?"
There has been some accusation that Hersh has gone soft on the CIA in recent years -- but Sherman shows that its more a matter of Hersh now criticizing the CIA for incompetence, rather than simple evil. Sherman's whole discussion of Hersh's career is very balanced and nicely textured -- its worth reading in full. It can be found in
http://www.cjr.org/issues/2003/4/hersh-sherman.asp
I have to say though that for all his flaws Seymour Hersh is the best journalist in America. From My Lai to Abu Graib, he has constantly gotten the goods.