Yes, I'm confused even though I lived half my life in the part of the United States that the term originated.
I feel like it's not only that you don't get it, it's that you don't WANT to. Look, if someone calls you white trash, literally the last thing that should pop into your mind is that "OMG he's racist!" No, that doesn't make any sense at all, because what they are literally criticizing you for is NOT your race, it's your utter lack of class and civility. White trash people are those who are stereotyped as living in trailer parks, with trash and a car on blocks in their front yard, with some mangy-ass dogs, four kids running around half naked and wild, barely literate, who entertain themselves by watching Honey Boo-Boo on TV when they're not getting smashed on cheap beer or whiskey, who have essentially no decent values and rely on shallow and materialistic ways of thinking. But amazingly they are the same race as other white people, even though it's mostly white people who would call them white trash. I know, it's totally a complicated term. :yesOf course as I said if it had nothing to do with race, then the word white would not be there.