There is a legitimate conflict- I agree that security decisions and issues of what should be kept secret must be reserved for those at the top level who truly know how to make the appropriate choices in making information secret, who understand the sensitivity of the information (I will not derail this post by making the obvious allusion), and who make their choices without a political agenda. Absolutely! Yet if a person at a lower level finds convincing evidence of a true and very serious crime, say treason, and believe that the secret designation by the top administration is likely a political one, what are they to do? There are whistle blower laws that apply in other contexts and I can't help but feel that there is an argument for anyone in an organization questioning a "secret" being withheld from the American public. I do feel the correct first approach to to contact others in the government who do have the appropriate security clearance/decision making power and ask for them to intervene. Yet morally, I have a lot of sympathy for Winner.
And what her private views are have nothing to do with the accuracy of the document. I see her as primarily motivated by patriotism based on learning of an enemy of the USA trying to interfere in our democratic process. It is not as if her voting of Bernie puts her beyond the pale- they are totally irrelevant to her actions, which may or may not be legitimate as such, not due to her political views. Personally, I think the document itself is important for the American public to learn about, and II can only see a minor security risk. Russia already knows that we believe they interfered with the election, although the details of what we have learned may not all be known to them. But of course I am not an expert.