It's pretty funny that basically every other country in the world asks for citizenship in its census but this is seen is as a right wing issue in America, shows how far to the left America is on some issues.
It goes back to the fundamentally racist jus sanguinis policy in most Old World countries vs. jus soli in the United States (and most New World countries). The default assumption in jus soli countries is that most people are citizens, and questioning citizenship is inappropriate. The default assumption in jus sanguinis countries is that people who don't "fit in" aren't citizens, so questioning citizenship is normal. That Europe and much of the rest of the Old World world has calamitously bad immigration policies compared to the U.S. and most other New World countries is not really news.
It's amazing for how long those policies have been bad and how at one point, basically all of their problems could have been blamed on them.