The truth is that "the truth" has consequences. In this case posting 1000's of private documentation that contains information that people may use in a decision on whether or not to go to war is wrong . Would it have been right for Wikileaks to publish the fact that Prince Harry was in Afghanistan? No.
If they want people to know the truth I think that is great and I personally believe that people should search out the truth. However sometimes knowing the truth can, will, and has in the past cost lives.
Quick scenario: Wikileaks releases secret information that says that the crown prince of Saudi Arabia wants America to bomb Iran. Iran takes objection to this (quite rightfully) and instead of waiting for America to bomb them, they decide to test their first Atomic weapon on.... You guessed it, Saudi Arabia.
Now tell me; Is it right for Wikileaks to release all this information?
With great power comes great responsibility; Wikileaks are not being responsible. This could cost people their lives. Maybe even the people at Wikileaks. Not all countries will take this lying down.