The Grammys' rap committee didn't want Macklemore nominated in the show's rap categories, the AP reports. An anonymous source said "most" members of the committee felt Macklemore & Ryan Lewis should be barred from rap categories "because of their success on mainstream radio and their appeal in the pop world." Arguing that Macklemore's music found more fans in pop than rap, the rap committee initially rejected Macklemore & Ryan Lewis' submissions, but their decision was ultimately overturned by the general Grammy committee, who, in a "landslide vote" decided the duo should receive rap nominations.
In an essay about his participation on the Grammys' reggae committee, journalist Rob Kenner sheds some light on why the rap committee might hesitate to nominate an artist best loved by fans who don't usually listen to rap. Kenner describes an "unwritten rule" of committee voting. Emphasis ours:
Be careful about green-lighting an album by someone who was really famous if you don’t want to see that album win a Grammy. Because famous people tend to get more votes from clueless Academy members, regardless of the quality of their work. This is especially true in specialized categories like reggae and, to a lesser extent, hip-hop, where many voting members of the Recording Academy (who tend to skew older than the demographic for rap music) may not be well acquainted with the best releases in any given year.
For his part, Macklemore has preemptively ceded the Best Rap Album competition to Kendrick Lamar. "If we win a Grammy for Best Rap Album, hip-hop is going to be heated. In terms of [that category], I think it should go to Kendrick," he said in an interview with The Source earlier this month.