Maybe so, but it will probably work, to an extent.
If the government can stop the mass media from reporting anything from wikileaks, most people won't find out. Of course most people will have heard about the new leaks, but unless it comes on tv or in the paper, most people probably won't bother to go through the information and find out what's what.
If the government let the media do what they please, the media would build up to the leaks, then give nice and easy to understand summaries of the leaks letting people get the leaks without them having to do anything they wouldn't usually do. Without the media, by the time the leaks actually come out, a lot of people will have forgotten about them.
Of course it also makes the government look bad, but no worse than we already knew they were.