I don't get the Hillary-hate. Yes, she's a consummate, lawyerly politician; yes, it would be depressing to have Clintons in the White House again because it would bring back bad memories of the 1990s. She isn't that inspiring (speeches or policy proposals). She's very careful and calculating, in part due to living in a political free-fire zone for the past 25 years. Yes, it's distasteful and exasperating to vote for her because she's the lesser of evils.
As to why supporters of Hillary seem to be so rare, keep in mind that we're just now emerging from the primary season, and Sanders and Trump were the only candidates generating much enthusiasm. Now that the primaries are over, and the choice is between Clinton and Trump, voters will, with a great deal of resignation, get serious about choosing between these two.
I suspect that if Trump won, he would govern in a more mature and civil manner than his behavior so far would suggest. What makes voting for Trump out of the question for me? His Supreme Court choices. I think there's every indication that his nominees would be right-wing, corporate friendly and hostile to civil rights (though maybe liberal on social/sexual issues). That's just who he is; that's his background, those are his interests. He's a rich, super-entitled member of the uppermost reaches of the 1%.
I do give Trump credit for trying to shake up the political system, which most everyone agrees is simply no longer working for the public interest and for the middle and working classes. That shake-up is inevitable; I just hope it doesn't come through Trump.
Finally, a lot of people are frustrated that their choices for president always seem so uninspiring. There are some structural reasons for this, such as the two-party system. Given that the USA does not have a parliamentary system, a competitive third party would be tough to accomplish. Another problem is the electoral college system, and the practice of many states of giving the winner
all of the electors, not assigning them proportionally. For example, I live in Texas, which for the time being is completely dominated by the Republicans. If Trump gets 60% and Hillary gets 40%, all of the electoral votes (100%) go to Trump. That means that my vote for president is completely meaningless and without effect. Furthermore, the presidential candidates essentially ignore a heavily Republican or Democratic state like Texas and New York, because the outcome is never in doubt. (BTW, that also means that
everyone's presidential vote in Texas or New York is meaningless.) Only the half-dozen or so "battleground" states will decide the election. I think if more people understood how the presidential vote works, there would be even more cynicism and apathy than there is today. Take a look at this site,
http://www.nationalpopularvote.com/ , which goes into much more detail. They also have a plan for reforming the electoral college that would actually be constitutional.