You seem to have a view that the world consists only of (a) people who claim things, and (b) people who believe them, and that there’s no difference between types of claims.

The claim of someone who says they have the word of god is hearsay and there’s no way to figure out whether they do or not. The claims of someone who says they’ve followed the scientific method are verifiable by others. If they claim that their experiments show tiny blue tetrahedrons make up all matter, other people can check. Nobody can check if god talks to the first person.