B/c few entities have the ability to do it. The public relies upon the press to act as a check against government power and corruption. This is why we have the 1st amendment.

The cozy relationship between the press and government rots away at the foundations of freedom and democracy. It is a moral duty of the press to expose corruption at all levels.

Notably, the NY Times (one of the few papers with the reach and scale to do meaningful investigation of US Government corruption) has written a variety of slander pieces about Julian Assange, strangely deciding to pick sides. The paper had the ability to act as a responsible intermediary between the leaked data and the public, but instead chose to flagrantly side with government power.

...This is a more subtle form of the same arrogant jingoism (and American flag pin wearing foolishness) of Fox News reporters.