Typically its a generational thing, meaning most young people who have grown up with underground and now mainstream hip-hop & rap inherently appreciate the artistic qualities without necessesarily understanding them technically.
For older cats, who remember when there was no mainstream hip-hop or rap, basically I have noticed that it seems the more white you are, the harder it is to get.
Western art music (white music) is based on melody, harmony, and harmonic progression. While rhythm is of course also integral, its subtleties in white music are no where near the level of depth of our african counterparts (traditional african tribal music).
In african music, there is a huge rhythmic element absent from white music. It only begins with things like insane syncopation, inflection, multi-timbral and throat singing, poly-rhythms...hell, the way they click their tounges in some cases in considered on par with the greatest piano and violin virtuosos.
So come the evolution of blues, jazz, and the freedom of the black slaves in the US, hip-hop, rap, and now I would argue even drum n' bass have direct roots in reggae, dub, blues, jazz, folk, gypsy music, indian music, and the like.
So modern hip-hop may sound like its all about 'bitches and hos' but if you dig a little deeper, you'll find some amazing stuff. Imagine a guy busting out in unison with a John Coltrane sax solo at 10,000 miles an hour!?
