A simple answer is two words: "Yes, but ..."
And, that's with everything implied by folk psychology tropes by adding "but" after the "yes."
So, I'm going to break that out more, with a nutgraf of sorts kept down at the bottom.
So, here we go ...
Journalists don't just seek out, gather and collate information.
They analyze it.
Then they write about it.
Assange did little of the analysis or writing work even with the initial information he got from Chelsea Manning, when he had much greater degrees of freedom of space, time, and working space than he does now.
Writers, and even more, editors, make judgment calls with information they receive. Some of those judgments are whether the material is true or not. Others are whether it would be harmful to release some of it.
I think Glenn Greenwald, for whatever reasons, has gone overboard on what Edward Snowden information he and Laura Poitras have chosen not to release, but, they have made a judgment call. I think they went way beyond just going overboard when they yanked the rights to the Snowden information from the eyes of everybody but themselves — ie, no Guardian, no Intercept, etc. Frankly, wouldn't be surprised if Ken Silverstein is right and the Russkies honeypotted Snowden but that's another story.
Assange? In the past, at a point after his working space freedom started to close up but was not that tight, made decisions to dump information without redactions, and in the case of some Afghanistan material, was rightly criticized for an endangerment factor.
That's just one issue. As Wikipedia's page on Wikileaks notes, it's released Social Security numbers, credit card numbers and more. With basically no effort at redaction.
In short, he's as much a sub-Redditor as he is a journalist.
I also said in my initial piece on the actual "yes," that to the degree it's true, he's actually like a Beltway steno in reverse in some way. He's an opiner, not a news writer, to the degree we consider him a journalist, by what he gathers, and what he solicits. I've already, along with others, criticized him for not seeking and encouraging leakers inside places like Russia and China. I've criticized more his response to that initial criticism. Today, Russia has a home-grown version of something like Wikileaks — no thanks to Assange.
I can't prove what's behind that. But, between that, and his likely lies about the source of the initial round of 2016 DNC emails — that VERY likely source being Russians, whether or not on paper officially connected to the Russian government and not a DNC employee — Assange is at least open to the charge that he deliberately refused, for clandestine reasons, to help get a Russian version of Wikileaks started. Countervailing that would be the idea that if Assange was hands-on, on getting such a movement started, even with alleged anonymity, he could turn people in.
(That said, this is a good spot for a side note.
For all the people not only (rightly) denying Russiagate, but claiming Russia can basically do no wrong? I'm thinking of the specific issue of the claim that the Internet Research Agency has no direct connection to the Russian government. Big fucking deal on a nothingburger claim. China says the same thing all the time about its Red Army hacker squads.)
Counterpunch publisher Jeff St. Clair here has the number of not only Assange, but of people like that, and of the people who believe them:
I think Julian Assange's lowest moment was his inculcation of the Seth Rich conspiracy in some of the more credulous precincts of the Left. The strangest part of the affair is that if the preposterous Rich conspiracy had proved true, it meant that Assange would have outed his source.
Now, the likes of Mark Ames and Aaron Mate haven't signed off on Seth Richism, just the IRA type stuff. But, I do Google from time to time.
When Assange, or Wikileaks as its mouthpiece, HAS made editorial judgment calls, sometimes they've been off the wall. Like criticizing the leak of the Panama Papers.
Here? I suspect 190-proof red-eyed jealousy at work — as one motive.
Another? I'm still not ready to call him a Russian agent, but the Panama Papers' attacks on Russian businessmen (Mafiyya, let's be honest) is another reason Assange attacked their release, claiming the U.S. government was behind this, which is nonsense. Ken Silverstein had done some work on Mossack Fonseca even before the main Panama Papers leak and I KNOW he's not a government agent.
And? Vlad the Impaler Putin himself cited Wikileaks in fighting to defend Russkies with likely government ties. Again, Assange may not be a Russian agent, but he has certainly left himself open to accusations of such.
Jealousy is not a one-off issue with Assange, either. Edward Snowden was among those who criticized Assange for not sufficiently curating and editing leaked materials, and Assange claimed Snowden was pandering to Hillary Clinton.
Good journalists also have good ethics. In promoting the totally base and vile Seth Rich conspiracy theory, primarily to try to cover up that the initial DNC emails came from a Russian hack, Assange has shown his lack of ethics and his willingness to outrightly lie. (Given that nobody — not Assange, Patrick Lawrence, Adam Carter or anybody else that I know of — has tried to explicitly claim that the spearphishing attack that got the later emails was not Russian-done, why the lie was engaged in was perplexing, too, and remains so.)
And, related, Silverstein thinks Snowden, if not originally a Russian agent, got compromised at some point, so who knows?
Wikipedia also raises the issue of whether or not Assange is anti-Semitic. First, to the Assange nutbar fanbois, I know well myself the difference between anti-Zionism and anti-Semitism, and the use of the latter as a weapon against people calling out the former. As with Russian agent questions, at a minimum, I think Assange has left himself open to anti-Semitism claims.
And, per Andrew Stewart at Washington Babylon, Assange is definitely anti-feminist, which ties back to his troubles in Sweden (which have now been opened legally AGAIN!) He's also, weirdly but openly, anti-atheist, at least on Tweets that Stew collated. And his call for more births in Europe make him come off a bit like an Anders Breivik, or other white nationalists in Europe and America. If this is journalism, it's op-ed journalism.
Assange is also an idiot at times. In the link above, I mentioned his previous issues with lack of password protection. His belief that Trump would give him a pardon or something for all the DNC leaks further shows this idiocy. By the way, to riff on Janice Joplin, schadenfreude is just another word for someone else who arrogantly still has plenty to lose.
Journalism is also a collaborate effort in some way. Even at a small community newspaper, the managing editor will bounce ideas off other staff. A publisher will be a check, if the editor doesn't voluntarily include the publisher in his or her advisors.
Assange is managing editor and publisher all in one, with a sycophantic, perhaps even cowering, editorial board, even if Kristinn Hrafnsson is listed as editor in chief.
Journalism is an art or a craft, not a science. It will always have a demarcation problem, per philosopher friend Massimo Pigliucci and his writings (in the sciences) on demarcation issues.
I wouldn't put Assange outside the bounds of journalism. But I would put him in the borderlands.
And I'm comfortable with saying that.
And if we stopped calling him a journalist, I'd be OK with that, too. We don't call Snowden one, nor has he ever presented himself as one. And, that's that buried nutgraf.
So, why IS Assange a journalist, if he is one, and Snowden is not? Is it anything other than Assange having an organized backing behind him and Snowden not? Is it Assange-generated PR related to that?
Here's option three — we call Wikileaks a journalistic organization but don't call Assange a journalist. For my personal value, this has the petard-hoisting factor of, on paper, forcing Hrafnsson and others to defend Wikileaks separately from defending Assange.