It was treason because he stole and released classified documents pertinent to national security. Period.
How is a video from a helicopter showing the pilots gunning down reporters and civilians "pertinent to national security," and why was it classified, other than to hide a crime?
Yes, I would consider outing an active CIA agent (plume) as treason as well...
The Iran-Contra scandal itself was an act of high treason...
The IRS targeting Tea Party individuals is illegal and immoral...
I didn't ask how those things were all treason, I asked how releasing information that these crimes all happened treason? Manning released information about a crime. He didn't commit the crime. Why is his releasing information about a crime treason, but the reporters releasing information about these other crimes not treason?