Refugees are routinely used as cheap/free labor in order to undermine the local labor movement. They're easy to exploit, isolate, and ultimately vilify when economic conditions in working class neighborhoods deteriorate.

You don't have to bend yourself into a mental pretzel to see a large influx of skilled professionals as a threat to your personal welfare, in an economy that rewards administrators who pursue the smallest possible labor costs.

What's more, these cheap laborers are often held up as a population that needs to be heavily policed. That creates a boom economy for people in law enforcement. The boom in law enforcement creates a patronage network that runs back to the wealthiest plutocrats and their political allies.

This creates a virtuous cycle for capitalists

• migrants drive down wages and drive up civil unrest
• unrest invites a big police force which cements "cop" as a member of the professional working class
• police brutalize the low-cost migrants while landlords gouge them for a healthy profit
• new wave of migrants come in to repeat the cycle and further stratify local wealth.

The end result is functional serfdom.