Salon is nowhere near the mainstream media. It's a punchline for people who think Slate is mainstream, and those people are themselves not in the mainstream.
The NYT piece you cite is not about vaccination, and notes on that subject only that RFKjr wrote an antivax piece that was challenged.
I suppose you could use the same argument for rolling stone, but frankly it doesn't matter. Look at the UVA rape case from earlier this year (covered widely). The RFK piece on vaccination was published originall in rolling stone. The hagiographic prose the NYT writes about the author (kennedy) and the editorial selection of the piece by rolling stone lend these ideas credibility regardless of the flaws in the articles. Again, look at the UVA rape article earlier this year (published: rolling stone) and see how much coverage it got in NYT, WaPo, LaTimes etc. Its worth noting That WaPo debunked alot of the Rolling stone reportage ultimately, but that just goes to show that not all newsrooms are single minded/purpose entities.
Lastly, if you look up (and read) the footnotes in my earlier not, you'll se that there is a clear link between the academic critique of 'journalistic integrity' and the anti-vaccination example, insofar as 'false balance' is a well defined sub-topic of that debate. Under the Wikipedia article for that...you notice (rightly or wrongly) that of the examples given, the anti-vaccination quakery (eg, kennedy in rollin stone etc) is a "well worn" example.
In other words, a commenter making reference to this is not making any novel or original argument that needs "footnotes". Footnotes are useful when there is a more subtle point, a nuance or something that is not obvious. Footnotes are less called for here, as a simple google search will attest.
The NYT piece you cite is not about vaccination, and notes on that subject only that RFKjr wrote an antivax piece that was challenged.