whether assange qualifies as a journalist is/could be relevant because the first amendment specifically protects the freedom of the press. "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press"

ergo, if assange is a member of the press, it's constitutionally harder to go after him than if not.

no one is saying that if he's not a journalist, the separately-mentioned freedom of speech doesn't apply to everyone else.