Sadly for Hillary, there are a few things about her that set her up for male opposition.
Hillary has declared that there is a "war on women". Such implies that men are the invading violators in this "war". Men who aren't involved in such a "war" find her over-generalization offensive and divisive.
The media picks up this "war on women" attitude and spreads it into every home in America. This associates her with such divisiveness, and the association is repeated, so that, like an onslaught, it's ingrained in the minds of the public. This may not be her fault .. maybe .. but, it still happens.
Hillary's website and her speeches single out additional special benefits she would enact specifically for women and at the implied expense of men .. but nothing of the same for men. Sure, she's pandering to her demographic for votes .. but it doesn't play well for a number of men. Hillary over-exaggerates that men have an "advantage" and that the playing field needs to be "leveled". This may be good for getting her likely voters to come out to the polls .. but it may increase the number of men who will come out to simply vote against her. Again, the media runs with this, often making it bigger than it is.
Hillary's website and her speeches also present her attitude that there is a "war on color", meaning that non-White people are being invaded and violated by White people. Again, she's only trying to pander to her demographic, and her managers' logistics might thereby be sound. However, there are consequences in that when you combine her two "war" attitudes, as many of the men who don't like her are White. The media, of course, runs with this too, making her famous for it .. or infamous, depending on your point of view.
Hillary also is frequently referred to as "Monica Lewinsky's ex-boyfriend's wife". Both a number of men as well as women have a difficult time with her rather codependent passive response to her husband's affairs. Specifically to this thread, men find her weakness here unattractive.
Hillary is not the most attractive woman in the world. For many men, having an unattractive woman be the "boss" is asking for trouble as these women often have been hurt by men who wouldn't go out with them or respond to their affection .. or who cheated on them .. and the rage such women harbor often gets transferred and displaced onto other innocent men, and Hillary can have a snarky attitude that implies there's contempt lurking below. So she, understandably, scares men. If she was very attractive and kind toward men in general, non-sexist, non-divisive, and her policies didn't contain so much compensatory female favoritism, she would score better with men.
Her policies, being liberal, are also going to be opposed by right-wing men in general. Women are the overt leaders of liberals, with men more background supportive. But men are the overt leaders of conservatives, with women more background supportive. Thus she will get her share of conservative male detractors, simply for political policy reasons.
These are the greatest reasons Hillary has a problem with men .. and, to be completely accurate, that many men have a problem with Hillary.
Yes, I'm sure there could be other reasons listed .. but these are the main reasons she has such a low response from men.
Trump doesn't score well with women, and likely for similar types of reasons simply played oppositely.
