> The only way you could justify a statement like this is by ignoring at least two events that both hit closer to home to Americans - the kidnappings done by the Gestapo in the 30s and the Mafia in the 20s.

Both of those predate the invention of the particular use of “disappear”, a passive voice construction implying an active voice transitive use with an animate direct object (the active voice form of which was not actually in use yet, but is sometimes seen since), which was invented in the late 1970s specifically in reference to the Dirty War in Argentina. It has been used since somewhat more broadly, but only because it invokes the intense coverage (including in the American media) of the Dirty War.

While certainly for a large number of young and/or particularly historically ignorant Westerners the specific referent may not be immediately recognized, the upthread comment that “ To anyone as allegedly historically literate as the author, especially one who's focused on the crimes of US imperialism and foreign interference, there is no question they would be familiar with what that term specifically refers to - the dirty war in Argentina” is absolutely correct.