Census has been weaponized in the past
Historical Canadian census records were used by the federal government and Indian agents as tools to identify, locate, and track Indigenous children to enforce compulsory attendance at residential schools.
Census records were actively weaponized against Japanese populations during World War II. For decades, government agencies denied any involvement, but historical and statistical research eventually proved that census data was directly used by both the United States and Canadian governments to facilitate the forced uprooting and mass incarceration of people of Japanese descent.
Census data and demographic records were heavily weaponized against Jewish people, most notoriously in Nazi Germany and occupied Europe during the 1930s and 1940s.
Historically, the relationship between the census and military conscription is deeply intertwined. In fact, the very origin of population counting in many ancient civilizations was not for statistical curiosity or resource distribution, but for two specific state mechanisms: taxation and conscription.
Etc.
So don't be too judgmental about people who ignore the census.
Here's one: Fine Me - I will NOT Fill Out the Census: https://www.youtube.com/watch?v=NggW9eV7X6s
Those who ignore history are doomed to repeat it.
"The job of intellectuals is to question authority, not to serve it." Carl Sagan