You are full of justifications, from "Americans do the same" to "I said the usual way" and how "some may identify their ancestry nation". You are full of shit. Sorry.
What's with the 'sorry'? I'm not here to 'justify' anything to you.
Just because Hilaria was born in Boston, from American parents, doesn't obliviarate her growing formative years in Spain. Her perfect Castilan says she grew up in Spain. It's impossible for her to have the accent unless she grew up in Spain.
From Wiki:
*Baldwin was born Hillary Hayward-Thomas on January 6, 1984[1] in Boston, Massachusetts, to Dr. Kathryn Hayward and David Thomas Jr.[2][3] Her mother grew up in Massachusetts and spent her career practicing medicine there; she was an associate physician at Massachusetts General Hospital and assistant professor of medicine at Harvard Medical School prior to retiring from both positions in 2012.[4] Her father was an attorney with a BA in Spanish literature from Haverford College and a JD from Georgetown University; together the couple founded International Integrators, an integrative health firm, in 2013.[5][6]
Her paternal grandfather was David L. Thomas, Sr.,[7] an "American with roots in the country that pre-dated the American Revolution" and her maternal grandmother Mary Lou (Artman) Thomas was from Nebraska.[4][8] She has a brother named Jeremy Hayward-Thomas.[2]
Her parents moved to Mallorca, Spain in 2011.[2][9]
Baldwin attended private high school at the Cambridge School of Weston in Weston, Massachusetts.[2] She later attended college at New York University.[10] While attending NYU, she was on the ballroom dance team.[11]*
It only took me a few seconds to check this. You could have done the same. Hilary Thomas was born and raised in Boston. She only spent time in Spain on holidays, like millions of others. She is not Spanish by any definition. She is American.