("So why haven't they charged her? Why didn't Comey charge her under Sessions if Lynch would not allow it?")
Some might suggest that a Democrat Administration with A Democrat AG who just had a private meeting on the runway at a airport with the accused's husband, who is a ex President himself, did NOT want to see the Democrat party's candidate for President charged with felony's a few days before the election.
Others might think that someone like Hillery Clinton could have dirt on others and use it to barter with in order to avoid charges. We may never know, unless a new FBI Director and new AG were to reopen the case. Personally I think she is simply to big to jail, and would take down many others with her if she were pressed.
But perhaps not, other Democrats have been elected from their jail cells before in the past.
In regards to Comey reversing his position on recommending charging Hillery, after twice saying he did not recommend charges under Lynch. I think it would look really bad to change his position 360 degrees after being so public about not recommending charges under the old Democrat Obama administration. How would Comey explain this complete change of position only a few weeks after closing the investigation?