This is a lot of it. Urban liberals see rural working class as backward and racist and uncultured. Just having a non-coastal accent (eg southerners) is treated as a marker of low character in our media. I recall how GW Bush’s accent was treated, as do many rural voters. Look at the discussion here, it’s about “those people” being too dumb to vote for their own interests. Unsurprisingly, people resent that.