When these cities literally enact a policy of obstructing justice, their officials can and should be prosecuted.
Federal laws you don’t like don’t just become optional because you say so, and entering a country illegally or overstaying a visa is a crime under federal law. This isn’t something unique to the US where the US government is literally Hitler; it’s a well established international norm.
Miller’s reasons for supporting this are the wrong ones, but he says isn’t necessarily incorrect under federal law as it stands. Not to mention that supporting brazen violations of the law like this is part of the reason why Democrats have alienated ordinary voters and let the far right basically take over.
If you read the article, they were almost never awake at the same time since they were on different shifts. That was mostly likely done on purpose.