2) I am not going to lie; I would genuinely give religious Christians a "free pass" or at least condemn that less because European countries have all been historically Christian. It is far from ideal and may make me seem a bit of a hypocrite but whatever.
Ay, there's the rub!
Of course, France is a country that makes secularism by far a huge part of its national identity; so part of "being French" certainly involves leaving religion at home (which includes not wearing christian necklaces, or head veils, or turbans, etc).
Yes, and that's a bad thing.
However, assuming he has the "standard" parents came home in the early 1900s and does not have anything Italian about him other than perhaps a surname; yes, I don't think he should really identify as Italian-American.
I mentioned him precisely because he seems to have plenty Italian about him.
I am not fully against hyphenated identities for people who came as kids, or who have both parents born abroad, but by the time you get to grandchilcren, shouldn't they identify fully with the country they were born and raised in, instead of a country they have literally nothing in common other than a surname (and often not even this!) and having very distant relatives?
Are you aware that those grandchildren relatively often are literally citizens of the 'ancestral' country? Among other things.