Philosophy branches out from metaphysics, through epistemology out to ethics and then politics. If Ayn Rand's epistemology is incorrect, her politics will be even worse. So why do you like her if her philosophy is wrong?
What the above actually means is: "If you have any mistakes in your theory of epistemology, you cannot make good moral decisions". And it's not just that that is nonsense; it's justificationist nonsense. It requires a Perfect Theory of epistemology. Presumably before you can have that, you have to have a Perfect Theory of metaphysics. All your beliefs must be true and justified. This may not look obvious at first, because the person I'm quoting is not structuring their assertion like an infinite regress, but rather as a kind of infinite progress. They require one to have perfect version of the theories with the most reach before you can have good theories with less reach.
Obviously the problem with this assertion is that it's illogical, but it is important to see that the nature of the illogicality is "knowledge is justified true belief". That way it's easy to ignore such a misconception; instead of having to wade through all the tangled strands of nonsense, you can simply understand that this hatred of mistakes is unwarranted, and that in your philosophy you are not searching for any Ultimate Truth, and that is sufficient.