Even ignoring the fact that ICE is a rogue agency that behaves thuggishly and routinely lies to judges, the United States has spent a long time having a tacit policy of only partially enforcing its immigration laws. Suddenly enforcing them as written would fundamentally not work. It would be cruel, since the people you've effectively let live here for decades are now parents of American citizens who have the right to live here. It would also be self-destructive, because large parts of the country function because of the labor of those individuals. Despite the fact that Trump's administration is full of people who advocate remigration (ethnic cleansing), the pro-business parts of his administration have made a lot of concessions to avoid deporting so many people that they'll disrupt farming (though there's been a lot more than 0 disruption).

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.