Here you could be talking about atheism or Rand's work. In either case, you're out of place.
Atheism deals with propositions. Belief presupposes a proposition. It's that proposition which atheism ultimately dismisses as unreasonable. The matter of your so-called "unknown unknowns" is irrelevant to atheism qua atheism.
Rand's work, as with huge swaths of written non-fiction broadly cross-category, is written in very much a positive sense... because she bases the entirety of her philosophy on axioms which she finds to lead irrefutably to her conclusions. Why would she write in such a way as to allow people who draw rabroad
her conclusions to be "right" when she finds that alternative conclusions rest on either faulty premises or flawed logic? As far as she's concerned, it is a metaphilosophical given that "if A then B" - and it is a metaphilosophical given that "A" - so why should she write with any but the most fanatical conviction that "therefore B"? I mean ... you can criticize her writing style for a lrabroad
of reasons, and if you want to argue her reasoning or her premises, fine ... but to "just nrabroad
accept" her because she means what she says is outlandishly fucking stupid.