We don't live in a "show your papers" society. Nobody carries their passport around with them. Driver's license, sure, but that's not proof of citizenship to the Feds. ICE detains people because they're brown, and then laughably asserts that they wouldn't do so if people had evidence of their citizenship. I bet half the country would have a hard time producing clear evidence of citizenship, and 99.9% couldn't do it on the spot.
It's a fascist, racist organization dedicated to terrorizing brown people.