Ego and narcissism are perhaps the most common and strong traits in leakers and betrayers of confidence. Financial motives and motivations to avoid scandal pale in comparison. So much so that I find it laughable clearance investigations focus on the latter at all.
So if a man that sacrifices his life and career for the common good is an egoist and narcissist, what does an altruistic and giving person looks like? Like a corporate drone? Like a conspirator in an effort to control the minds of all free citizens?
The strongest common trait in leakers is belief. They believe in something. They aren't willing to sit back and witness some people damage society as a whole.