I was thinking the same thing. Some of the living Watergate figures, like Liddy, could make a case that Felt was guilty of unauthorized release of classified information and that therefore their prosecutions were unjust and should be overturned. It does sound as if Felt did this more out of personal pique than out of abstract idealism about administering justice.
I thought Liddy speculated it might have been John Dean.
It doesn't even have to be classified. It is a crime to release personal information about a federal employee.
I came away from the article with the same impression. I don't think I like the idea of the FBI working hand in hand with the WP.....