Having dabbled in immigration law once upon a time, I can say that the system is indeed completely fucked. Back then (like 2014) it seemed less insidious, and more like a lot of people doing the best they could in a broken system (even if the law was kind of jacked up). Now, though, things seem to be getting a lot worse.
In a statement, ICE officials said their enforcement activities are conducted “with integrity and professionalism” and “in compliance with federal law and agency policy.”
When you can make up the rules, of course you comply with them!
Sadly, many citizens, much less immigrants, don't know the limits of ICE power. Their warrants are not judicial, and are therefore not really worth much. An arrest warrant from a court allows police to search the home where they believe the person to be; an ICE arrest warrant does not.
One of the interesting side-effects to Trump's "deport everyone" approach is, as the article points out, a lot more cases. Which means that fewer people are actually being deported, since the backlog means it takes longer to get a disposition (and they can't be deported without appearing before an immigration judge). But as cynical as I am about the criminal justice system, this shows how much worse it could be without any court oversight.