I don't think "here's the dictionary definition" is usually a useful argument, but in any case it's hard for me to see affirmative action as "excluding" white people, since it's generally practiced in fields where they remain dominant.
If the issue is that people are suffering prejudice based on their names then a better solution is to mask the names during the initial screening as opposed to making it a point to hire someone based on race. I'm sure that a study exploring the effects of different "white-sounding" names would see differences too.
Also note that the study does not draw any correlation between racism and the judgement of a name. Given people's tendency to be averse to things they are not familiar with, it's possible that it's a problem of someone not being comfortable with a culture they don't understand and not necessarily a problem with skin color.
Do you really think that people are biased with respect to names, but then forget that bias as soon as the person enters the room?
Also, it's unclear to me why it might be better to be prejudiced against African-American names than against African-American skin tones. Your definition of racism appears to (a) include policies that disadvantage the dominant group (white people), even when motivated by a goal of correcting historical injustice and insufficient to undo their/our dominance, but to (b) exclude actions that disadvantage the historically oppressed group (Black people), even when motivated by prejudice, as long as that prejudice isn't explicitly based on skin color. Do you maybe want to reconsider?
I agree that in a world where racial discrimination is a thing of the distant past, affirmative action wouldn't make sense. But that's not our world. See for example: http://scholar.harvard.edu/mullainathan/files/emilygreg.pdf