Italian here, first time I see the word "plagio" used like this. We usually say plagio when someone does not respect a copyright, e.g. I wrote a book and someone copy the majority of book to write its own book
>The word “plagio” is not of recent coinage. It derives from Roman law, which also created its present ambiguity, because “plagio” in Italian means both “mind control” and “plagiarism,” as in “My book has been victim of plagiarism.” It was the same in Latin, except that the meaning of “control of a human being” came first, and the meaning of “plagiarism” came later.
>Responsible for this confusion was a satirical roman poet of the first century CE called Martial. In his epigram no. 52, Martial used the word “plagium” humorously and metaphorically. Just as those who try to pass off another person’s slave as their own are guilty of “plagium,” Martial said, so should be considered those who pass off a literary work they copied from somebody else as their own. They also commit “plagium,” protested Martial...
vittima di plagio, plagiare una persona, etc are all in common usage (and subject of study in psychology)
However there's a page on Wikipedia in English [3] and Italian [4] and also Treccani mentions this meaning in Plagiare’s thesaurus [5] only.
If feels like it's meant as "to enslave", either physically or mentally.
1: https://www.treccani.it/vocabolario/plagiare/
2: https://en.wiktionary.org/wiki/plagium
3: https://en.wikipedia.org/wiki/Plagio
4: https://it.wikipedia.org/wiki/Plagio_(ordinamento_penale_italiano)
5: https://www.treccani.it/vocabolario/plagiare_%28Sinonimi-e-Contrari%29/EDIT: on second thought, there is the idiomatic expression "una persona è stata plagiata" which might be what the article is about. It is used in the sense of someone who's led astray by "evil" influences.