It does seem stupid, but I think the Italian prosecutor is holding her parents. She may have to return to testify on their behalf... but yeah... she needs to stay away.
The whole case is just bizarre, and that prosecutor is an overzealous wingnut. It’s just mind-boggling that Italy allows a prosecutor to appeal a not-guilty verdict. That kind of double jeopardy is the worst kind of third-world nonsense.
Her parents are being held in Italy? On what charges?
Take it down a notch.
That's the nature of code law, which is just as "first world" as common law.
There are aspects of common law that code jurisdictions also consider strange or backward - like prosecution in absentia.
And there are specific American practices - like allowing attorneys to coach witnesses before they testify - that are considered beyond the pale by foreigners, both common law and code.