Assange is alleged to have actively recruited hackers and directed them to find particular information from particular sources. Among other things, agreed to assist Manning in deriving a password from a hash file. (It is irrelevant whether he succeeded or not—the crime of conspiracy is complete upon taking the first substantial step toward achieving the goal of the conspiracy, such as passing the hash to someone else for cracking.)
According to the indictment, he was closer to running an operation to expropriate sensitive data from all over the world than being a journalist neutrally publishing documents that people sent him.