(note- this isn’t how I feel, but I do know a lot of conservative types, and have grown up in a conservative area)
I think this is part of it- a lot of conservative types are, or aspire to be small business owners, and maybe if the dice roll well, medium or large business owners. Like maybe starting out as a one-man plumbing business, and ending up with a dozen or more plumbers under you in your company. Or owning some dry cleaning shops, or maybe a general contracting business.
So they tend to view policies that increase taxes, regulation, or other burdens on businesses as a direct threat to their future prosperity- at best, things like increased environmental regulations are viewed as making it a little bit harder to achieve their goals, and at worst, as a direct attack on their livelihoods.
The government is generally viewed as an antagonistic force- one that takes tax money, isn’t perceived as providing services/benefits in proportion to that tax money that was taken, and that tends to levy unnecessary or disproportionate regulations on all sorts of stuff that isn’t their business (in their perception).
So when they hear about people in the inner city needing MORE welfare, or more social programs, or anything like that, they severely bridle at it. They feel like they’re already paying a lot in taxes and getting little in return, while the inner city crowd (who also happens to have a different skin color) sucks up the difference, wants more, and cries about their treatment.
Now it’s all a matter of perspective- we know that the last paragraph isn’t true, or isn’t true in the way that the conservatives are perceiving it. But they don’t necessarily have any way of knowing- from their perspective, they (conservatives in the suburbs or rural areas) are working hard, trying to provide for their families, and become prosperous, all while the government keeps siphoning off a large proportion of their income as tax, and outside of police, fire and essential services, doesn’t really do much in return. They don’t get WIC, they don’t get Medicaid, they don’t get food stamps, they don’t get electricity or water assistance either. Their children aren’t getting free lunches at school or free school supplies either.
All they see themselves getting is the essential shared services that everyone gets, and feeling like they’re getting a raw deal on that, because there’s a large chunk of people who use that and don’t pay taxes, and suck up resources for other stuff like medicaid, free lunches, etc… And on top of it, they have higher crime rates, higher teen pregnancies, etc… all of which is viewed as both symptoms and causes of the problem.
It’s not so much a lack of compassion, as it’s a feeling of unfairness that then mutates into hostility and disdain/condescension. It’s almost always as a group conception- not individual racism in most cases.
So when Trump shows up and basically says “Fuck those people” in so many ways, they’re all on board- he’s basically saying he agrees with them, and is doing things to remedy this.
The reason they’re so hostile toward (white middle class) liberals, is because they view liberals as enabling this behavior and actively working against their prosperity in favor of this other crowd (blacks, mexicans, white trash) who don’t act like they should. There does seem to be an element of racism here- I definitely perceive a bit of a betrayal feeling, like white liberals are not sticking up for their own somehow.
How is that a reason? Personally, I don’t particularly like Hillary Clinton or Joe Biden either. But it’s obvious on well-documented empirical grounds that Trump is far more ignorant, mendacious, destructive, irresponsible, malicious, delusional, incompetent and unethical than either of them. So if it’s a choice between one of them and Trump, it would obviously be thoroughly stupid and reckless to choose Trump.