> When people used to say "disappearing people off the streets", they were trying to paint a picture out of Orwell's 1984, where the secret police not only drag someone off never to be seen again, but no one can or will acknowledge that they were ever born in the first place.
I don't know which people you are talking about who did that, but people I’ve seen doing it were more likely to be implicitly (or, fairly often, explicitly) referencing historical real-world authoritarianism like Pinochet’s Chile, not dystopian fiction like 1984, when they talked about governments disappearing people off the streets.
Though common to all three (authoritarian history, dystopian fiction, and the present American regime) is concealment of the fact of detention, the location of the detained, and sometimes the fact of the detained’s death