The FBI also said it wouldn't recommend prosecution against Hillary, and the DOJ isn't prosecuting, but everyone under the sun knows Hillary broke the law. The FBI's inaction isn't indicative of an absence of criminality.
Her negligence is worthy of disciplinary action, sure. If this had been discovered while she was still Secretary of State, she may have been fired. But she wouldn't have been sent to prison over it.
Lots of relevant discussion here: https://www.quora.com/Are-Republicans-right-to-be-outraged-t...
"Hey FBI, please investigate your likely future boss and friend of your current boss and be honest please!"
"Hey DOJ, I'm the president, your boss, and I appointed you, but will you investigate this other person I also appointed, even though we're all friends and in the same party? Oh, and please don't be biased."
The opportunity for corruption is just too great when an administration investigates itself.
So not to spell out the obvious... but, either she's the next President, and very clearly not a felon, or she is not the next President, and exactly one Administration will have a chance at proving she is a felon, until the statue of limitations runs out.
Personally, I think it's a crazy bet Hillary is taking. Her life is on the line with this election. The best thing Obama could have done for Hillary is charge Hillary himself, and not let her take this risk, and then pardon her if necessary. When she ultimately sees her day in court, you probably want that to happen under a friendly Administration. Some sort of plea agreement perhaps. Double jeopardy is required for Hillary to be safe from a long statue of limitations.
I don't think the President can pardon someone who hasn't been charged yet. So even if she wins this election, she could still be charged by the next administration.