It really isn't hard to understand if you actually talk to people who live in the middle of the country.
Couple of streams
1. Government is broken on the left and right and is unresponsive to the needs of huge swaths of Americans. This also includes the all forms of mainstream media. These people see themselves as left behind, Trump speaks to that anger.
2. Some people are REALLY sick of the political correctness around many issues. They see Trump as the ultimate troll of the political establishment and press.
3. Some people are supporting Trump because he seems like a giant bomb to blow apart the political establishment in the hope that what comes out of it will be more libertarian vs authoritarian instead of this phony left vs right.
4. Some people just want to put breaks on "progress for the sake of progress" and would like to get back to more traditional values.
Trumps popularity has nothing to do with ideas or policy, it is complete political revenge on the establishment. The funny thing is that once Sanders goes away, you will see some Sanders voters voting for Trump....
I am sure people here completely HATE Milo Yiannopoulus but
he actually explains why people support Trump in this video:
Honestly, the left is as equally guilty as the right in creating Trump.