It amazes me how much people will vote against their own self-interest. Also, something a lot of the SV and educated crowd don't understand, but immigration disproportionately affects uneducated workers by dramatically increasing the supply of labour with workers willing to work for low wages (they are partaking in wage arbitrage vs. their home country). Lots of industries that are dominated by immigrants and illegal migrants today used to offer far better income and living conditions 2 generations ago.
If people truly cared about the plight of the uneducated working class, there'd be taxes on wealth, incentives against rentiers, far higher minimum wages (to discourage wage arbitrage by immigrants from poorer countries) and maybe even basic income. Or a limit on the supply of labour (ie. slow down immigration) and tariffs to combat outsourcing. The first is a better outcome IMO, but the second is a perfectly rational reaction.
But hey, bringing up actual economic effects of social policy is racist and bigoted, right? That's why the current bourgeoisie doesn't understand movements like Brexit, populism, etc...
Edit - for the record, I like left-wing solutions better. I very much admire and agree with economists like Piketty. But most left-wing parties in the west have really dropped the ball. They're beholden to the same rich donors, and gloss over economic policy by championing social justice instead.
Edit 2 - some back up for my assertions: https://www.nber.org/papers/w3761