In my post I said "preferentially choosing people of one race over another". Sure the hypothetical Country Club lets in some blacks, but it really sets a much higher bar for them. It sets a lower bar for other races.
That is affirmative action. Don't believe it? Look at the data unearthed from admissions data provided during the Harvard AA lawsuit. Asians must pass a much higher bar than certain other groups.
The question is, if it's not ok for the Country Club, why is it ok for Universities?