Let's say you have Elizabeth, a 18-year-old black woman who lives in a council flat in Tower Hamlets and you also have Joe, a white working-class 18-year-old man from Bolton. In reality Elizabeth and Joe probably share a lot of experiences and understandings but populism has convinced Joe that he has more in common with Jacob Rees-Mogg than he does with Elizabeth, and populism has ignored Elizabeth entirely, (often questioning her legitimacy as a UK citizen) and has crafted the perception that all the left are elite.
BIt off topic as I'm digressing into UK politics, but I think a lot of this is transferrable to discussions about the Democrats and the rust belt in the USA.
Your point is broadly speaking right, but I think only half of an analysis. Aditya Chakraborty, the Guardian's economics editor (whose analysis I always find to be bang on), wrote a fantastic piece post Brexit, where he pointed out that for Joe in Bolton (I think it was actually Sid in Sunderland), in real terms he was worse off than ten years ago. The economy (barring a highly artifical housing boom in the SE) still hadn't clawed its way back from where it was before the 2008 crash. So when the north of England poor (or for that matter, poor in inner London boroughs) said "well, where are all these marvellous benefits in terms of jobs and trade and income that the EU is supposed to bring us", they had a point about the absence of a trick-down effect into their own lives, even if they were pinning the blame on the wrong culprit.
And in a sense, Joe and Sid were actually right - it is far from clear that globalisation and internationalism, acting in tandem with close to free-market capitalism, are a force for good if you're poor. And I think the left too often ignores that. They're so wedded to "internationalism good" that they ignore the more nuanced message that "internationalism co-opted by capitalism in a wage/job conditions race to the bottom is often bad for the poorest."
The suspicion among people at the bottom of the heap that a lot of the stuff better off liberals push as a liberal economic agenda is mainly good for better off liberals isn't entirely without foundation, I think. Where they go wrong is then ascribing the causes of the problem wrongly (saying it's down to immigration, rather than unfettered capitalism).