A government won't give up on malicious acts just because it lacks accurate census. The United States does a lot more surveillance and oppression than EU countries that have national ID and mandatory ID documents.

The lack of a comprehensive population database only seems to hinder the actual useful civilian bureaucracy, not law enforcement, intelligence services, or ICE. The latter just grab anyone who looks brown enough.

In the US, where race is entirely defined by skin pigmentation and there's heavy segregation ("redlining") of living quarters, sure: databases aren't necessary. But in places where race is defined by heritage or culture, things which can be disguised by the targets of a regime, these databases are a vital part of any serious ethnic cleansing operation. I don't remember the statistic in IBM and the Holocaust that compares Jew survival rates in occupied countries with versus without digitised censuses, but the difference was stark.