It seems like there are two possibilities: there are hundreds of people who are missing, presumed killed and the bodies are disappeared in the swamp
Or
The ICE program is far less successful than reported and the amount of people doomed to Alligator Alcatraz is inflated.
Given how inept this regime has been and how frustrated Stephen Miller has been over his incapable gestapo, the people likely never existed. Numbers were likely made up to make the bosses feel good.
An important thing to note about the source I used is that the Washington Examiner is a right wing rag that supports Trump. So seeing the news creep into the right wing echo chamber means it can't be ignored. Stevie is big mad others aren't as blindly racist