In my opinion, this may possibly explain why Comey didn't bring any charges.
He merely tossed all of the violations out into the public domain and, as a result, she will be tried in the court of public opinion; and, as that video shows, not favorably. He could have simply handed the conclusions of his FBI investigation to the Justice Department without a press conference and allowed that agency to decide whether or not to press charges. But, by having an unprecedented news conference, he ensured that what she did wouldn't be swept under the rug. He also gave Donald Trump, the Republican National Committee (RNC), and any Trump SuperPacs, all the sound-bites they need to keep prosecuting her in that fabled public court. In fact, as of this writing, the RNC has already released this ad:
If Hillary Clinton does lose the election because of her server problem, the Democrats may regret that she wasn't charged so that they could have had the opportunity run someone else for President.
Morning Joe eviscerates Hillary Clinton in wake of brutal FBI report about email conduct: https://www.youtube.com/watch?v=maVuOWDOHL8
Transcript: Statement by FBI Director James B. Comey on the Investigation of Secretary Hillary Clinton’s Use of a Personal E-Mail System: https://www.fbi.gov/news/pressrel/press-releases/statement-by-fbi-director-james-b.-comey-on-the-investigation-of-secretary-hillary-clintons-use-of-a-personal-e-mail-system