I don't get the whole Olympics part of this discussion. Of course the Olympics is about representing your country and national pride. It is less so perhaps for sports like Basketball over gymnastics or track and field but still a part. Compare this to David Ortiz rallying Boston after the 2013 Marathon bombings. The team represented Boston. That is a good thing. It was a showcase for "Boston Pride" just like the Olympics is a showcase for each country's national pride. I don't understand how there could possibly be a problem with this.
As to Giannis, I am no sociologist so I don't know if there is some underlying bias against Giannis because is is from Greece or Luca or any other foreign player. These two in particular seem pretty popular. Hockey is a big time sport with very international rosters. Doesn't seem to be an issue there. Was Chara less popular than McAvoy? How about all the Canadians, does this not apply because they are North American and not as foreign? And wasn't there another thread about Shohei Otani also? I don't think this is an issue and see no reason to try and find one in this.