
Reagan understood that, rather than try to stop people flowing in, the gov. Could just make sure that immigrants and minority groups ended up in the same neighborhoods. The Reagan administration recognized that they could exploit whole communities of oppressed people, and turn it into a resource.
We have historically used minority/immigrant communities as places to put the things that our privileged (typically straight white) communities would take issue with. Things like industrial waste disposal sites, meat processing plants, industrial facilities that cause health issues. All of those can get shunted into communities that are less likely to make a fuss about it. So rather than generating change to a more sustainable society, we can profit off these communities while keeping them down.