The New York Times has a deep-dive into Comey’s FBI suggesting what we've long suspected; Comey's letter to Congress "informing" them that the FBI had "new" information in the long-running hunt for something damning in Hillary Clinton's emails was done not out of high-minded concern for the country but two considerably less noble concerns; distrust of Democrats in the Justice Department—especially Attorney General Loretta Lynch—and protecting the department itself from criticism.
Fearing the backlash that would come if it were revealed after the election that the F.B.I. had been investigating the next president and had kept it a secret, Mr. Comey sent a letter informing Congress that the case was reopened.
He most emphatically did not, of course, acknowledge that his FBI was actively investigation the Donald Trump campaign for potential collusion with Russian hacking efforts. The public deserved to know that the FBI was investigating the next president—but since Trump wasn’t going to be president there wouldn’t be any point in making announcements about that, now would there?
“In my mind at the time, Clinton is likely to win,” [ex-senior FBI official Michael B. Steinbach] said. “It’s pretty apparent. So what happens after the election, in November or December? How do we say to the American public: ‘Hey, we found some things that might be problematic. But we didn’t tell you about it before you voted’? The damage to our organization would have been irreparable.”
Yes, we certainly wouldn’t want the public to know you’d found out something “problematic” about one of the candidates but that you didn’t tell anyone until after the voting was over. Just think of how damaging that would be.