As to why or what the pay-back was?
I don’t think he made a single penny off this effort.
On the why, he felt he was personally righting a wrong done by the establishment intelligence and military community.
In the 1980s and 1990s...you rarely saw this type of behavior with military members. Since the 9-11 period, the wars in Iraq/Afghanistan...there’s a growth of people who are second-guessing events, and feel empowered to correct ‘wrongs’.
For every hundred in the military intelligence sector...there’s probably one-percent who have the feeling that ‘correction’ is required. Other than threatening them with a life-long sentence in some remote Montana federal prison....I don’t see how you will motivate this small group to correct their own behavior.
They don't seem the sort of people I'd want to hang around with: vane, self-righteous and humorless, I'd expect.
The thing is, we're also indebted to such people for revelations of bad things done in the past, and we need to keep them around for the future.