Dude, it's an authoritarian tactic as old as time. Create a law that can't be followed, and then selectively enforce it on those you deem to be your political enemies. 

U.S. immigration policy is completely unworkable. 

Here's a test. If you're in, say, Honduras, and want to come to the U.S. "The Right Way"^TM, what's your first step? 

No looking it up or cheating, and remember that the White House took down all the web pages in other than English.