Of course, the FBI should have opened the E-mail investigation case back up. It's job is to investigate federal criminal activity and the potential thereof. The only thing that is truly mysterious about this whole event is that it found plenty of wrongdoing, but never pushed for a criminal indictment. I guess Director Comey values his life too much.
Yes, I agree that the FBI should have re-opened the case regarding Hillary Clinton's emails. New information was found that the FBI did not have when the completed the investigation the first time. The FBI was doing the right thing by making sure they had all the evidence that they needed to make sure they made the correct decision.
No, they should not have opened the case back up in the first place because Clinton was nearing the end of her campaign. The FBI tried to alter the results of the election because they tend to vote Trump. The only reason they reopened the case was to cast doubt about Clinton.
They only opened the case up becasue they were pressured by outside sources who seemed to believe that these new emails from Anthony Wiener would incriminate her. They had already conclueded that she did not violate any laws, and that the e-mails did not contain sensitive information. And of course, C stands for confidential, not classified.