Kind of akin to the idea that communism and fascism are divergent branches of the same underlying philosophical and economic premises, you can see this same stupidity in action from both the progressive left and the populist right.
Either way, the underlying premise is that somebody is cheating you out of a job, and somehow it involves employers and immigrants colluding against the native-born American working class.
The Progressives blame employer greed, saying that they're just trying to underpay downtrodden foreigners, in order to profit. They believe they can just force employers to pay higher wages, thus evening the playing field so that American workers are seen as a better deal.
Populist conservatives actually agree with all of that, believing as they do that the boss man will screw them over at any opportunity, but instead of trying to force employers into higher expenses (which they recognize will likely result in higher prices and fewer jobs), they prefer to restrict immigration -- thus reducing competition for jobs and securing their own opportunities.
Also... For a subset of the populist conservatives, reducing immigration has the added benefit in segregating people of different ethnic backgrounds and limiting the cultural changes that come with an influx of people from other parts of the world.
Progressives, meanwhile, get to rally coalitions of American working-class voters around the idea of hating "rich" people (employers), while still claiming to welcome immigrants (even though their policies are intentionally geared around making it more difficult to hire them).
Also, frankly, there's a decently large subset of Progressives who are also racist and just don't want immigrants in their communities... but who don't want to say so publicly.
Point being: BOTH the progressive and conservative populist viewpoints are the same, incorrect, zero-sum observation. The only actual difference between them is their proposed "solution". And even then, the net effect is to make goods & services more expensive and harder for immigrants to find work in the US.