Economics

As it always has since the 1776 bourgeois revolution, the capitalist class largely runs the state, and many of them exploit immigrants:

1. For their cheap, compliant, and politically & legally impotent labor
2. To weaken the bargaining power of the domestic labor force and suppress its wages
3. To pit domestic labor against immigrant labor, which distracts some of the domestic working class from its real enemy: the capitalist class

Some portion of the capitalist class publicly rails against “illegal” immigrants while privately exploiting them. It’s kayfabe.