This is downstream of the fact that the US government just doesn't work well. Problems fester, and are unsolved. Immigration policy hasn't made sense for longer than I've been alive (and I'm 40+).
Imagine that you find that the water supply in your town was built illegally, because the former mayors prohibited the building that was necessary. You may think that is a travesty, you may want to enforce the law strictly in the future, and force the issue, rather than working around it. But what you will not do is tear up the water system and leave the city without water.