Because they DO have whatever data they want: From Palintir.

Preventing the government from accumulating a database is meaningless. But it doesn't matter anyway. Even if they didn't have any data, that's not an impediment, because there is zero pushback to literally blackbagging people off the street and sending them to another country. They just want to harass brown people and you don't need a damn database for that. Bootlickers have eyes.

This bullshit about government databases has always been a meaningless distraction. Oppression doesn't want to be precise or efficient, it's counterproductive to the goal of scaring people into compliance.

Tell me, how do you believe they are stymied at all? They've arrested anyone they want.