I didn't make any comments on the utility of racial classification, just that the classification isn't perfect, leaves groups out, and where you decide to draw

I didn't make any comments on the utility of racial classification, just that the classification isn't perfect, leaves groups out, and where you decide to draw the lines between them is often arbitrary. Race is an oversimplification of a complex system, but even an oversimplification has value. Seems like you have a pretty good grasp on my assertion here.