He wasn't wrong though. Martok was the one who demanded blood tests in the first place; but when he was introduced in Way of the Warrior, he was already a Changeling! They were never effective!
Michael Sullivan (of "delete the wife" fame) says it in Lower Decks 4x01. And a Betazoid gift box says it again in 4x03 (after similarly living an entire fabricated lifetime in a moment).
Not that it really matters, but the commercial is for Old El Paso.