Fact checking all the facts is an extremely broad scope. A small mom and pop company is hardly able to support such a mission unless they happen to be multidisciplinary experts/geniuses. I always seemed a bit doubtful about some of the conclusions drawn from that site.
Or instances where insufficient evidence is used to draw an absolute conclusion.
I've seen them actually commit the latter where they fact check a politician's prediction based on an expert projection as if the expert is infallible.