They
claim they are not backed by any governments, but decline to say who is backing them. Just as an example I came across yesterday, the San Francisco Standard is "not backed by any government and rely on donations", but their funding comes from a billionaire venture capitalist. The same claim could be truthfully made by a site backed by a Russian oligarch just as well. And regardless, there's no evidence.
I agree that Wikipedia's mechanism has its challenges; anybody who knows the site does. But it's vastly better than "any publication from 1980" because every edit is tracked, the citations should be available for all to see, and people can object to and/or edit bad content.
Just as an example of how a book from the olden tymes could go wrong, consider Trump's "The Art of the Deal". It sold more than a million copies, but its ghostwriter took 20 years to admit that it was a lot of horseshit: https://www.newyorker.com/magazine/2016/07/25/donald-trumps-...
Wikipedia is way more auditable than that book or most books from that era. And way more auditable than The Gray Zone that you've chosen to cite.