Well, obviously there are different styles of hip-hop. I mean, we all speak in English in America, but we have different lingo and accent sometimes. That's all the difference in the style of hip-hop from Soulja Boy to Flobots to Dead Prez is. Style is the only difference. Just because it doesn't sound exactly alike doesn't mean it's not hip-hop. Plus, that song you linked relies heavily on the beat, which is what I described hip-hop as.