As for Sinner's Italianness, we always have to repeat the same things.
His ethnicity is Austrian but he is Italian because South Tyrol has been part of Italy for several decades, so I don't understand what is so difficult to understand in all this.
If someone doesn't like the fact that South Tyrol is part of Italy, write a letter of protest to the UN.
Also because if we are to argue about the sense of belonging of the various lands, the nations as we know them today simply wouldn't exist.
But then the hilarious thing is that tennis is one of the sports with the most multiracial protagonists.
According to some geniuses on the forum, is De Minaur Australian or Spanish?
Tsitsipas Greek or Russian?
Zverev German or Russian?
Shapovalov Canadian or Russian/Israeli?
Sampras American or Greek?
Agassi American or Iranian?
Berrettini Italian or Brazilian?
Chang American or Taiwanese?
FAA Canadian or Togolese?
McEnroe American or Irish?
Tiafoe American or Sierra Leonean?
Korda American or Czech?
Alcaraz himself, if I'm not mistaken, has Arab descent on his father's side (and his and his father's features also make us suspect this).
Ergo, why only Sinner's Italianness is discussed remains a mystery, even more so when he has always said he feels Italian and is proud of it even if his mother tongue is German.
I bet that in this forum no one has ever discussed Seppi's Italianness even though he in turn comes from the same land as Sinner, perhaps because Seppi is a more Italian surname or simply because Seppi did not become number 1 in the world.
In fact, for the Austrians themselves, Sinner is the South Tyrolean when he wins and the Italian when he loses.