I base this assertion on the epistemic notion of knowledge as (shortening here for convenience) Justified True Belief.
Are you suggesting that enlightenment, if it existed, would be somehow based on justified true belief ("knowledge")? If so, wouldn't that imply at least the possibility that one could become enlightened, if there were such a thing as enlightenment, simply by reading and understanding the "correct", "right", or "true" theological text or scripture?
If, just for example, you think that "non-attachment" is a higher good then "attachment," then you will have failed to understand some very important truths about the nature of human emotions, and their role in our very existence. And that cannot be considered "knowledge" in an epistemic sense.
Are you suggesting that emotions must somehow be "attached" to function appropriately? If so, why would you suggest that?
Are you suggesting that one could not be enlightened, if there actually were such a thing as enlightenment, unless one made some kind of a value judgement about "non-attached emotions" versus "attached emotions"? If so, why would you suggest that?
If you think that there is some sort of human soul that somehow, eventually (in whatever fashion various religions suppose) reaches some final, ultimate state, then you will have failed to know anything at all about what evolution really is, and what a "soul" likewise really is -- and realize that they cannot, in any universe, exist together.
Are you suggesting that enlightenment, if there were such a thing, would necessarily depend on the existence of a "soul" and/or that souls "reaching some final, ultimate state"? If so, why would you suggest that?
I contend, therefore, that so-called "enlightened people" may suppose that they know something that others don't, but that same supposition is equally true of everybody else, too, and is therefore (through reduction ad absurdum) false.
You've lost me there. Could you re-phrase your point please?
You seem to be basing your rejection of the notion that enlightened people know something that others don't on some model of enlightenment I'm not familiar with. Could you expand on just what that model is, please?