according to her That's why he lives on an island, has never drunk alcohol before and why he generally displays "savage" behaviour like trying to rape Miranda. It's also why the play treats Prospero enslaving him as justified.
It's a common interpretation of the play (to read it as about New World contact/imperialism) since the early 19th century. Latin American critics, performers, and artists even started reappropriating the figure of Caliban as a positive symbol and critique of Western imperialism in the 1950s. Currently, it is pretty much a standard scholarly reading of the play. Are you looking more for literary criticism (whether or not we should read Caliban as a New World figure) or a history of how Europeans viewed New World peoples in the time of Shakespeare?