Jane — I see where your correspondent is coming from, but I don’t think these other forms of “preference” pose a problem to the conservative (or at least, my own) critique of affirmative action.
One, many conservative critics do oppose these other kinds of preference. Dinesh D’Souza, for example, has come out against legacy admissions. And many of the arguments against affirmative action apply regardless of the criteria used for the preference. Mismatch theory, for example: If a bunch of unqualified Midwesterners are dropping out of East Coast schools, that’s just as bad as unqualified minorities’ dropping out of law schools.
Two, this argument fails to recognize that due to our civil-rights laws, a libertarian view of race-based affirmative action is impossible. I oppose affirmative action in the current climate, but at heart, I’m of the “it’s a free country” school of thought: If you’re running a private school (which all schools should be), you should be able to base your admissions criteria on any factor you choose.
In the absence of laws that force private businesses to accommodate customers of all races equally, that would include race; you would be free to admit only whites or only blacks, and to use preferences to tweak your merit-based selection criteria. But that’s not the world we live in. If an anti-discrimination law stops schools from implementing biased selection criteria against minorities, according to the Fourteenth Amendment the same law should protect whites.