Anyway, Rage Against the Machine was an early example of rap/metal fusion, and were a genuine social conscience. They get a lot of jeers because they belong to corporate giant Sony and people think they were just cynically making money from people's disaffection. But I give them the benefit of the doubt. Part of the problem is, I think, that lead singer Zack de la Rocha's voice sounds like he's an angry 15 year old. He's actually older than me, he was in his 20s when this song was released.
Killing in the Name is the perfect protest music, because it doesn't really deliver any specific messages, beyond oblique references to the Ku Klux Klan. Mostly the message is Rebel! Don't do what they tell you! And "they" can be pretty much anyone. But rest assured, they have other songs that are very specific about what issues they concern.