This phrase was implied until incontrovertible evidence to support them would emerge. But I do see your point on why it should be emphasized repeatedly. Profound discoveries such as the structure of DNA or the nature of spacetime are extreme examples (and no amount of peer review would have made the claims less crazy to those around at that time — which we now take for granted. But most other “discoveries” fall on a spectrum from incredulous to plausible but needs thorough review and evidence (tbd)