The Social Justice Warriors have raged over the past few years on what can and cannot be said. I think the majority of Americans who cherish free speech were outraged with rampant political correctness. So Trump comes along, who is probably one of the most un-PC people around, and you had people flocking to him. He could say the most outrageous things about women and/or minorities and few people batted an eye. Perhaps that's where the "Make America Great Again" struck a chord. Yes! Let's go back to an era where we can speak freely and not worry about what group we're potentially offending.
I also think there was a lot of pushback against Black Lives Matter. The President has pretty much wrapped his arms around the cause which pissed off a lot of white voters. Never side against law and order because we want to feel safe. People love that "thin blue line" that is our police force. I think most people can agree that wonton shooting of unarmed black men by the police is a terrible thing that should not be tolerated, but the movement went too far and started protesting and rioting when there were deaths of armed black men who were a danger to society. There were protests even when black police officers shot armed black men. And yet black men were being killed on the streets of Chicago every day by other black men, and there were no protests. White America saw the hypocrisy and the Democrats seemingly going along with it to garner votes, and so they voted for the more likely law-and-order candidate.
Finally I think there was pushback against the LGBT community. Gay marriage was grudgingly accepted because it has come to the point that almost everyone knows of someone who is gay. They are not sex-crazed child molesters who want to spread the gay genes to the children. They are good hard-working people just like straight Americans (just with a better fashion sense). But I think the transgender agenda pushed average Americans into the uncomfortable zone. It was one thing to say that "whatever gay people do in their own bedrooms is their business" but now they wanted to have "freaks" in their daughter's bathrooms and locker rooms. We have our own furry echo chamber. I think that almost all of us have friends who was trans that we love and support. That doesn't hold true for the rest of society. I think momentum will eventually swing that way just like with the gay rights movement, but it will just take a little more time. Once again, America seems to fall back on fear. We're the home of the brave until we're not. We fear what we don't understand, so it will just take time to build up that understanding.