In the eyes of the law, your race is considered immutable because it cannot be changed from its natural state.
This made me laugh. Being mixed the perception of my race is very mutable. People often have no idea what to make of my skin color, hair, or facial features.The day-to-day decisions I make influence that perception. The day-to-day decisions I make influence what I consider myself.
Some days I consider myself more black than white. Some days I consider myself more white than black. Some days I consider myself more mixed than either. Some days I consider myself neither black nor white.
The article does address this:
Race is an elusive, fluid concept, and the courts have been manifestly reluctant to define it. What, in the end, makes a person black? The 11th Circuit wrestled with the idea in its ruling, dredging up old definitions and emerging with nothing more definitive than that “race” is nature, not nurture.