The 'identify as' thing is interesting as a concept.
By way of analogy, some people feel a strong pull to a country, language and culture that is not the one they grew up in. My youngest dc is obsessed with Japan, teaching herself Japanese, planning to spend her gap year in Japan to improve her language skills. But however long she lives there, as a tall, blonde European, she will never pass for local, so it will always be obvious that she's a foreigner who has acquired very good linguistic skills and cultural knowledge.
So let's try a thought experiment and assume instead that she's obsessed with Sweden. She learns the language, spends a few years living there, and eventually acquires a native-like grasp of the language. Because she's tall and blonde, she fits right in, visually-speaking, so no one can easily tell that she's not a local.
But in neither case is she actually the same as someone who has grown up in that language and culture, regardless of how strongly she identifies with it, even if she makes it her home, marries a local, and acquires a new passport. The ability to pass is not irrelevant, because it will affect other people's reactions to her, but neither does it change the fundamental fact that her experiences are not collectively the same as a native of that country. And no doubt she would be swiftly reminded of that fact if she started trying to criticise or change the way things were done in her adopted home.
The Muscato/Alex/Ada car crash is the equivalent of spending a couple of months in France and then feeling the right to tell the French they're doing everything wrong and they don't really understand how to be French, so they should listen to them and learn how to do it better. And then they express surprise that the locals react badly to this. 