Hillary is stupid, not malicious. Let's assume for the moment that neither Donald or Hillary are actually as evil as we make them out to be.
Let's also assume for the moment that Hillary wanted to have an e-mail address with a domain name the added to her marketing value and she asked some egg-head if he/she could make it happen. Now assume that the egghead recognizes that she's the secretary of state as well as the former first lady of a two term president.
Now the egghead hears her ask for this and he's like "Well, I can't put that on our internal servers... what else can I do to make it happen?" Of course the egghead isn't a lawyer and he/she doesn't want to be cock-blocked by some manager and then go back to Hillary and tell her/him (still not sure) that he screwed up and now her dreams of having a her marketing slogan as a domain name for her e-mail will not be possible.
So... what does he do? Well, not being a lawyer or understanding what it would mean, he sets up a new mail server that would allow her to send messages to Bill like "Make sure you leave your cigars at your intern's house before coming home... oh and buy milk." without them ending up as public record.
I honestly wonder if the e-mail is the best thing they can come up with. Hillary isn't particularly exciting, but she's pretty awful at her job... unless you consider her job as Secretary of State as a personal self-promotion, optimal for ladder climbing... where in that case, she's great at her job. She has to have incredible amounts of crap they can use on her without even digging too deep. And the e-mail thing which I'm damn near convinced is basically technical incompetence as opposed to intentional malicious deception of the country.
Let's also consider that there's absolutely nothing related to the e-mail that will cause Trump to win. He's like the golden goose or the gift that keeps giving to anyone who opposes him. After all, I think that even Dan Quayle could have won running against Trump. Al Gore could have creamed him. Instead, the country leaves Hillary as the opposition and while she looks like she has a landslide, you know you suck when it's months before election and people can still identify a possibility that Trump could possibly win.
Democrats... what the hell were you thinking when you supported Hillary?
Republicans... what the hell were you thinking when you supported Trump?
You both had better candidates and you actually chose the most entertaining ones as opposed to someone you might actually want in office.