So that the rest of us can stay informed and sources can be protected. The tricky hit is regulating who is a journalist - bloggers here in NZ are running into this.
But do you trust the same governments hassling journalists at the border and rooting through their electronic data to decide who is, and is not, a journalist?
That's pretty much exactly what I was getting at - the journalists police the state, but the state polices the journalists.
What makes you think you can trust the journalists to keep you correctly informed?