I reject your Wikipedia links as authoritative sources on what constitutes a journalist as well as your contention that he's doing anything other than dumping documents (selectively).
No, because they read these papers and wrote the story on them. Wikileaks just provided mostly unprocessed data dumps. Explaining the story is a very big part of a journalist's job.
And, of course he does more than dumping documents. For example, he has to come by them (collecting as a journalist does), which is no small feat considering which kind of documents we are taking about.
If you're genuinely curious, just take a look at his work [1] to see that it's absolutely not "just dumping documents".
Are you going to provide any alternatives, because if not my rejection overrides yours. I would also point out that outright rejecting something without presenting either an argument or alternative why leads up away from productive discussion.
Every outlet, from the New York Times to Fox News to Slate selectively front-pages certain leaks and stories while de-emphasizing and outright ignoring others. Does that make them not-journalists too?
Check.
You can argue about whether his style is commendable or not (for codes of conduct see [2]), but that does not change the fact that he is a journalist.
[1] https://en.wikipedia.org/wiki/Journalist
[2] https://en.wikipedia.org/wiki/Journalism_ethics_and_standard...