Canada, by the way, does ask about citizenship on the Census. That doesn’t prevent it from being aggressively pro-immigration.
We are being fed a bunch of lies and we swallow them unthinkingly. “Only Nazis ask about citizenship on the census!” No, pretty much everyone does. And it’s all very reasonable and utterly uncontroversial. It only becomes controversial when you bring in an enormous illegal underclass that you want to exploit and socialize the costs. It’s harder to socialize the costs if voters find out how large it is. So you don’t let them find out. And invent a ridiculous story about how the number magically remains unchanged since 2004.