Something that people on the political left don't seem to understand about the nature of Donald Trump's support is that no amount of insults and name calling is going to dissuade his supporters. There's nothing anyone can say about Trump that's going to make him look any crazier than the things coming out of his own mouth, and clearly, his supporters don't care.
You can say or imply that his supporters are racists, fascists, homophobes, xenophobes, ignoramuses or whatever you like, but that's not going to work either. The ones who are don't care what you call them, and the majority who aren't are only persuaded further about how dishonest and sleazy the left has become, and that a tectonic shift in the system is needed.
Trump's unshakable support is in enormous measure a reaction to the vacuous identity politics that says that all white people and only white people are racist. It's a reaction to the type of ideology that espouses that feelings are more important than facts. It's a reaction to the campus 'safe space' idiots who think they have the right to shut down any discussion that offends them. It's a reaction to the cultural relativists who refuse to acknowledge that Islam is directly linked to Islamic terrorism and that there is no mainstream branch of that religion that doesn't advocate for the subjugation of Christians and Jews and the death of apostates and gays, and often mean it literally. It's a reaction to the dunderheads who refuse to recognize that people who violate immigration laws are flouting the law and instead insist on using the term "undocumented immigrant." It's a reaction to the eco-fascism that literally wants to imprison people for disputing their version of climate change theory.
That these things are problems is something that the political left and even the Republican establishment have consistently either failed to acknowledge are problems, or failed to deal with in any substantive way, other than to make them worse.
Hillary Clinton can promise change all she likes, but she's been firmly nestled in and benefitted from the system that caused all these problems for a quarter of a century, so it's hard to believe her.
Then along comes someone like Donald Trump, a political outsider, who promises to blow up the political correctness and the entrenched establishment. Despite all his many obvious flaws, just that is enough to make him bulletproof to many millions of Americans.
So if leftists really want to know why Donald Trump stands a very good chance of becoming the next President of the United States, they should take a look in the mirror. Because it's the political left who caused it.