The biggest issue in my eyes is that people are forgetting the real reasons why people voted for him; which is the collapse of the Post-WW2 Industrial Boom. There are countless cities and towns that no longer have large, paying jobs like they used to. This lack of security leads to the feeling of being forgotten, or turned aside and ignored.
Their truest wish is to return to what they would consider normal; work in the factory, go home to a loving family, do it all again the next day. The Hillary Campaign never addressed the issue dead on. If anything, she had made it worse by suggesting she would kill what little bit of the coal industry was left.
Trump did address it, but only in the vaguest sense. When he says, 'Make America Great Again', he's not presenting a solution, but an idea that rings true in the hearts of those most effected by Industrial collapse. He played off their fears expertly; blaming millions of others for the suffering of those in those small towns, and it struck a cord. Now these people are hooked on the idea that he might somehow save them; even if we are well enough removed from the situation to see that's not true.
Until these people are satisfied by a plan to somehow revitalize their societies, they will always vote for and support men like Trump out of desperation to save that dying dream. To win them over, someone has to give them a new dream that outshines the old. It won't erase prejudice, hate, and fear, but it will stabilize the effects long enough for real social change to be enacted.
I sort of rambled.
TL:DR - Collapse of Industry makes people desperate. Desperate people support idiots. Desperate people need help to not be desperate, so that they stop floundering and make real social progress instead of clinging to a bloated life boat in a toupee.