It's a freedom of the press issue, pure and simple.

…more than anything else, WikiLeaks is a publisher — a new kind of publisher, but a publisher nonetheless — and that makes this a freedom of the press issue. Like it or not, WikiLeaks is fundamentally a journalistic entity, and as such it deserves our protection.…
 http://gigaom.com/2010/12/04/like-it-or-not-wikileaks-is-a-media-entity/