[thaumasiotes]

> This is a difference in attitude between Americans and French when describing their countries

I'm not sure that's true - it appears to involve a legal distinction. I see many references to Algeria having been an "integral part of France" where other French territory wasn't. But I don't actually know what the terminology means. Anyway, I'd begin by looking to the legal status France tended to give to overseas territories, rather than the attitudes of the French, to explain this.

> Meanwhile I think a lot of Americans kinda-unconsiously barely even consider Hawaii and Alaska really parts of America, let alone the numerous non-state territories.

And this is a perfect case in point; Americans do consider Hawaii and Alaska to be really parts of America, because they have the legal status.