Trump won because Hillary Clinton was a shitty candidate. Not that Bernie Sanders was necessarily better, but he's not the one the DNC ran in the general. Hillary was.
Here are the objections I had to overcome when I voted for her:
* There was no way she could work with Congressional Republicans after 20+ years of GOP witch hunts.
* she's a neoliberal stooge, Wall Street's darling
* her supporters often talked about how it was "Hillary's turn" to be President. It doesn't work that way.