This actually isn’t too surprising:
The damage caused by the WikiLeaks controversy has caused little real and lasting damage to American diplomacy, senior state department officials have concluded.
….A congressional official briefed on the reviews told Reuters news agency that the administration felt compelled to say publicly that the revelations had seriously damaged American interests in order to bolster legal efforts to shut down the WikiLeaks website and bring charges against the leakers. “I think they want to present the toughest front they can muster,” the official said.
The official implied that the WikiLeaks fiasco was bad public relations but had little concrete impact on policy. “We were told [it] was embarrassing, not damaging,” the official added.
Italics mine. For the most part, the leaked cables were interesting and in some cases embarrassing, but as a lot of people pointed out in real time, not really all that revelatory. In fact, they mostly showed U.S. diplomacy in a pretty good light. Obviously American diplomats would prefer that private conversations remain private — and that’s perfectly reasonable — but in the end the WikiLeaks releases didn’t cause nearly as much damage as government officials claimed.