Hm, I interpreted it a little differently -- that she was talking about coming into the US to stay and live here ("we lived in Brazil for half a year" "we need to get to the US" "I want a calmer environment"), and that's a whooole different story.

This is pure guesswork, but it sounds like maybe she knew it would be a problem so she asked the immigration guy to just write her down as British to solve the problem, and he wasn't friendly about that suggestion and long story short no she can't come in the country, stay in Mexico, good luck, next in line please. And she interpreted it within this sort of framework appropriate to traveling around in places where she was used to, like a more smekalka system and being able to travel around like she wanted, and thought he was just being a dick about it and about the way he dealt with her in general, because of some personal racism towards her or something.

That would actually be a lot more charitable interpretation towards her than what I originally said "I'm Russian so I should get to do what I want." It might just be a genuine cultural thing that she ran into that she really doesn't understand. IDK though; I mean the truth is I'm purely just guessing.

But overall, I definitely think she was trying to come into the US to stay and live here, and having trouble with it (because it's real real difficult for anyone from almost any country, generally speaking), and that's why she's so upset.