Some truth conditions are extremely straightforward to verify, like "the sky is blue" or "holy shit come outside the sky is fucking purple wtf". The choice to share certain information might be loaded with implicit context and ulterior motives.

And after all, when two people talk, there's normally some context that both people are operating in, some common set of topics that are being discussed, and both sides would notionally agree about what would support of refute a claim.

It just seems that the article was written with an eye towards beliefs and facts asserted within large sprawling worldviews, and didn't stop to consider the opposite extreme of everyday, extremely mundane and tangible statements.