The Dragon-Blooded certainly tell themselves and each other that Exaltaion of the Dragons (or from the Dragons, if you prefer) is a sign of worthiness, usually in a context that links strength and moral worth i.e. "If you didn't Exalt, it's either because of a moral failing on your part or because you're weak, which is itself a moral failing." And they use this as justification for mistreating Dynasts who don't Exalt.
I think confirming this as a metaphysical truth removes value from the setting, however.
Although I don't have a problem with e.g. that Sidereal Astrology power that flags a soul for reincarnation as a Dragon-Blooded, because Sidereal judgement (and indeed divine judgement, because the existence of a mechanism by which Sidereals flag souls for Dragon-Blooded incarnations suggests a mechanism by which Heaven does the same on a larger scale) is not something the setting presents as morally sound.