Well said cos,
I've yet to hear this point so well made, and I'll be honest and say though I understood it to some degree, I only understood it well enough that if pushed about the subject I might have taken the OC's stance or one like it. It is amazing how important honest, respectful, yet blunt arguments are to helping one understand subjects like this.
If all the racism-awareness and related things in high-school (I would say 'and college', but I avoid them like the plague) had said this half as well as you did it would have made sense to me then. Unfortunately they always seemed more interested in making (the proverbial) 'us' feel guilty, not explain that we could do something about it.
Well done