Do we use the "reverse one-drop rule" when categorizing music?

i mean, if there's an artist or group whoce music consists of elements of rock, and elements of any music considered to have African-American roots, why is it automatically called "rock"? I understand the 'alternative' label, but straight rock? We're talking about bands like Linkin Park, Korn, brokencyde,Gym Cl Heroes, and the Flobots, who aren't even rock to me. We're not talking about Hinder, Staind, Nickelback, Seether, or Nirvana.