I think the explanation is simple. The agents assigned to the Anthony Weiner sexting case finally got around to looking at Weiner’s computer and Voilà, there were all of Huma Abedin’s emails! No doubt that many were of a classified nature, and they were residing on a Yahoo email account that could easily be hacked.
So what was James Comey going to do when he was notified through normal channels with the appropriate paper trails, ask his agents to sit on it until after the election because the public did not have a right to know this information BEFORE they voted for her?
No way would that be the RIGHT thing to do.
Comey had a bigger problem than “some of his agents” (whom he could threaten and intimidate.) The original investigation of Weiner was done by detectives of the NYPD. So LEO’s beyond Comey’s reach have seen some of this evidence.