The thing is: mainstream validation works. Whenever little-known sources are introduced, the chances of information being false or misleading just skyrockets. Moderator rings are often detected that way - all citing the same obscure publications that turn out to be factually incorrect.
The internal essay on "verifiability, not truth" [1] comes to mind. Determining what is Actually True is difficult and often contentious; determining what reliable sources say about the topic is easier and can itself convey important information when those sources disagree.
