You ever stop to think that maybe calling ~50% of the population of your country "a bunch of redneck retarded bigots" could perhaps have some part in it? The media pushing that narrative everywhere certainly doesn't help either.
I'm not a Yank nor do I vote or care to ever vote, but if I were and all I ever saw was every mainstream source of news and media, including sites like Reddit and apparently even HN, calling me a retard (which funnily enough is a pretty bigoted insult coming from the supposed moral & good side) and a bigot non-stop I'd probably say "fuck it" and vote for the guy too.
From where I'm sitting across the pond, the Republicans want stricter border control, smaller government, lower taxes, free speech (which itself is a loaded term that means different things depending on who's saying/hearing it), which is basically what the populist parties across the EU are promising as well.