Or: Shouldn't immigration be good for capital?
I know they'd prefer for migrants to stay somewhere where their labor time is cheaper to make better use of unequal exchange, but how is it better to spend so many resources on turning away refugees and immigrants that are desperate to work for cheap, than to simply let them get exploited? What are the forces at play that make capitalists invest in border security so much? Is it simply to keep an implicit threat on the existing undocumented immigrant population to make them more precarious and more exploitable?
Labor is imported from the refugee crises because it benefits capital, and can be used to play the the domestic working class against the migrant labor to distract. Those that are disappeared are likely deemed dangerous, while others who may have been discontented enough at home to disrupt a neocolonial situation are permitted for unknown reasons. Probably incompetence.