“White is not an origin. It’s a mental construct of privilege.”
Here Kingsolver discusses whiteness as a social construct and its relationship to privilege and oppression. Whiteness is not a genetic fact, but rather a cultural and historical construct that has been used to establish and maintain power dynamics. This includes how policies, laws, (yes our constitution too), and institutions have been designed to perpetuate racial inequality and privilege whiteness.
See also, W.E.B. Du Bois, David Walker, Frederick Douglass, and William Lloyd Garrison, Nikole Hannah-Jones, Jamelle Bouie, Ta-Nehisi Coates, Isabel Wilkerson.