Credibility doesn’t fall from the sky… it has to actually be earned by someone or groups of someones. Usually in the course of their decisions and activities.
Librarians don’t magically start off with an unlimited amount of it, such that they can completely ignore these considerations, and experience no consequences.
Even if they truly are all the most amazing, wonderful, honorable people on Earth, their credibility would still be depleteable.
Clearly not pseudonymous accounts on HN, nor can it be self declared otherwise 8 billion people can declare themselves to be ‘archivists’.
And why not? As far as I know, there is no barrier to entry to archiving things for your personal use from publically available websites.
Or are we talking about people who archive for public use?