Take a photograph, properly color correct it, and see what color the "white" actually is. It will vary a lot, depending on the color of light falling on the eye, and be tinged by the blood vessels in the eye.
I think he/she took offense to the "darkest part of the face" portion of the comment; which is clearly false for the majority of the earth's population, particularly since no one draws the iris white so the original comment was clearly referencing the "white" portion of the eye.
What it won't be is #ffffff.