A lot of times, when people say hip-hop, they don't know what they're talking about. They just think of the rappers. When you talk about hip-hop, you're talking about the whole culture and movement. You have to take the whole culture for what it is.
You would never hear any song played twice in the same way. The words were retained, but within a certain frame there was great latitude, and the musician could improvise to his heart's content; and the more the variations and combinations, the greater the musician.