I've only followed from afar in recent years but Italy has been naturalising largely shithouse players for a long time. I'm thinking here of Cameronesi and Iaquinta more than a kid who emigrated and grew up in Italy.
Black Italian players have been a thing for a while, Italy was probably the last big European country, as have guys with Arabic/North African names.
I reckon the Aussie with the Italian name wouldn't even be noticed these days.
It may be that Volpato doesn't have the clout to play for Australia until he is established. That doesn't mean he has to choose Italy, though.
I guess growing up in Australia he can probably read the tea leaves too...
Imagine he says yes and is built up to the 'Oz Messi' proportions by our once every 4 years football media, then he gets wheeled out to much fanfare in the cup and gets isolated in Arnold's putrid formation, gets starved of ball/opportunity and we get all tall poppy on him, it happens every time, oh big boots Cristian couldn't cut it...
It might just be this world cup is too soon? If he's being advised properly that could be the case.