And even if he did: If black artists are underrepresented in my CD collection relative to the frequency with which black people are found in the general population, does that make me a racist? To even begin to believe that it does, you have to first maintain that racial preferences somehow logically relate to music preferences; that racists avoid music made by black people, and that people who aren't racist don't pay attention to the race of the artist when evaluating music. Both propositions are ludicrous. Anybody who has been to a frat party knows that people can simultaneously a) entertain racist attitudes and b) enjoy listening to hip-hop music created by black people. (In fact, Merritt's argument is that the latter tends to reinforce the former.)
By the same token, perfectly reasonable nonracist people take race and ethnicity into account in their musical preferences all the time. Hopper herself, whom I presume Frere-Jones would certify is kosher when it comes to the race-music axis, has complained bitterly on her blog of the "whiteness"—which she describes as "purposeful," "icky," and "dangerous"—of Merritt's music. So, if it sounds dangerously white, we can infer that she'd like it to sound like something else. More … what?
The closest thing to a coherent argument that can be gleaned from what Frere-Jones and Hopper are saying is that a genuine respect for our common dignity and humanity requires that we enjoy listening to hip-hop, and that we bend our intuitive aesthetic judgments about music to a political will—like eating our vegetables and avoiding dessert. "Zip-A-Dee Doo-Dah" may be catchy and delightfully mindless, but an understanding of its context requires you to reject its charms. And Beyoncé may be trite and boring, but your subtle racist ideology provokes that reaction, so you must find a way to appreciate her music.
And if you can't? Try harder, cracker.