I am in a biracial marriage as is my son. And my daughter was in biracial marriage. In their cases, my son's wife is African, my daughter's husband was Nigerian. Our experiences are different, not to diminish her experience, but to be sure people don't think her experience is typical or standard or normal .
My mom was from Europe. I am 100% white and experienced a very similar response from young children in my mom's home town when we visited as children. They simply were not interested in making friends with "white Americans". Should I assume that hostility was due to my citizenship?
The hostility I experienced was real... but attributing to what caused it is a bit more subjective.
I was assaulted as a teenager by a group of African American kids my age on the way home from school as I had to walk by their neighborhood to get to my home. The reason was obvious, they said so, I was white.
Several of those same kids became close friends in later years, when we played on the same high school sports team. So were they racist and suddenly became "unracist"? Or was their previous "tribe" other African American children from their neighborhood and now we were teammates, part of the same tribe. They remain friends today and even apologized for their earlier assault on me.
I did not say her experience was wrong... what I said was it was one person's experience. And she gave no examples of the village being warm and welcoming to other couples that were not biracial.
I do agree with her the smaller the town, the harder it is for outsiders to fit in... the more different you are... the harder it gets...
If you are interested in doing some research on the subject there are some great studies on the fact that "biracial" couples have far more difficulty fitting in... the theory is that since most "tribes" are built around some aspect of culture, race, religion, etc., that we simply don't "fit in". But we have the advantage of being better able to work across these tribal groups. Anyway, I encourage you to do some additional research in the area.