I'm going to try to explain what I mean a little better:
There are a small, mostly insignificant number of swing voters today. There used to be more, but the polarization of society has pulled people more to one side or another. A lot of so-called independents are still voting straight-ticket, or at least are always going to vote one party in elections for federal office. Trying to go after the mythical middle of the road voter is no longer the method of winning elections. Sure, there were some Obama voters who went to Trump, and probably some Romney voters who went for Clinton, but fewer than the media wants to believe. In reality, elections are won or lost based on who votes. There were two unpopular candidates last election, and it had the lowest voter turnout in twenty years. Trump didn't win by getting a bunch of voters to support him, he won by getting a lot of potential Clinton voters to stay home. And he didn't need much help with that: she's phony and wants power, and that's been obvious since she joined the national spotlight with Bill. Sure, that's all politicians, but the good ones make you think that it isn't the case. They do a decent job of pretending they don't just want power, and we do a good job of pretending we believe them.
Hillary just ignores doing that dance, and makes it clear that she wants power for it's own sake. Like I said, that's no different than most politicians, they just hide it better. And that contributes to her lissues, as well as a certain degree of inherent bias*, and her long career as an establishment Democrat, and the dirty primary campaign against Bernie where the DNC conspired to ensure Clinton was the candidate. All of those things hurt her and kept her from getting the vote out.
On the other hand, Trump is REALLY good at using his opponent's weaknesses against them, and not caring about his own. Lack of shame plays a big part in his popularity, and going along with that is the fact that what you see is what you get. He's dishonest, vulgar, etc, but he doesn't hide it. In fact, it's a badge of honor for him.
She's helping Trump because his supporters absolutely hate her, more than probably anyone else in the world. Her actions help whip them into a feeding frenzy, so hopefully she disappears until at least 2021 in order to give Democrats a chance. Otherwise we're going to end up with another campaign against Hillary. And it also certainly doesn't help that her comments against Tulsi Gabbard reflect that same dirty campaign against Bernie. It's the establishment going against someone who isn't willing to toe the line on every issue, and it COULD make the eventual nominee look like they feel the same. Gabbard isn't polling well, but if her supporters are angry enough to sit out, and Trump voters are in an anti-Hillary frenzy, he's guaranteed to win in 2020.
There are a lot of ifs, but nothing in politics is certain other than politicians are scumbags.