I beg to differ.
https://www.meaa.org/meaa-media/code-of-ethics/
https://en.m.wikipedia.org/wiki/Journalism_ethics_and_standards
You may, but you can't ignore the fact that those things came centuries after freedom of the press was first codified in Western law making them irrelevant to considerations of the free press canon. Milton and Locke both wrote on the idea in the 17th century, the licensure for the press in the UK ended in 1695, freedom of the press was well established in The Colonies by the mid 18th century, it was formally enshrined in the Constitution in 1787, etc. Industry codes in journalism simply didn't exist until the 20th century. And they've never been the basis of some kind of reciprocal protection of rights in the common law canon. I focused on the English speaking world because it was the forefront of liberal thought and practice, but nations like Sweden and Denmark established similar press freedoms in the 18th century as well.
As such, any claim to a journalistic social contract is absurd on its face. Journalists abided by no code of conduct or ethics or standards for centuries yet the state and the law recognized the protection of the rights of the press. Even if such industry codes
now exist (and are in regressive countries enforced as law) that does not imply that failure to adhere to them forfeits well-established freedom of the press protections nor that those who have never subscribed to said industry codes do not also have those protections when they publish.
Whether or not Julian Assange is a "journalist" by any standard he was nevertheless obviously a "publisher" which grants him the protections under the freedom of the press. This is why journalism organizations and (non-repulsive) journalists are so keen to highlight the violations of his rights and include him within their sphere. Denying him the protections is the same as denying them the protections even if they claim to adhere to some novel industry code.