Of course they can. Hip-hop spoke to so many people in so many different ways. Music is music.
For the sake of argument, there are a lot of 60s-70s Soul musicians that HATE hip-hop. Their listeners in that age group primarily hate hip-hop. Should they be allowed to review hip-hop? What about the 20-25 year old kid, that calls us and our era

. Should they be allowed to review a Enta Da Stage or 4,5,6 or AmeriKKKa's Most, or Cuban Linx? These same people will call Reasonable Doubt or Life After Death the greatest albums ever, so how can you take it seriously? I think the review should be by a fan of hip-hop, but for a general consensus, get one from a fan of other music and combine the 2 reviews.