Warning: biased opinion!
I like music with a pleasant, recognizable melody from several different categories. One might call my musical "taste" eclectic. I appreciate good lyrics and understand the difficulty of crafting an excellent song.
That is only one explanation for my thorough dislike of rap "music". I would even go so far to admit that I loath it. But, not only do I dislike the melody (I give it the benefit of the doubt by using that word), I share Mark Twain's aversion to wailing cats. He did not mind the sound; it was the terrible grammar that he disliked.
It is amazing (and disturbing) to hear words not uttered in polite society blared over the airways. This is a particular aggravation during summer months, when car windows are rolled down and car radios are turned up. In non-English speaking nations, I'm certain that parents do not know what their children are hearing (if the children even do). It is treated as a cultural import from god's favorite nation and given music chart status.
If people knew what the lyrics really conveyed, they might ban its play. But, people in the US understand the words and let the crap poison the airwaves...