If you took a traditional church hymn such as Amazing Grace and changed the
lyrics to ones of perversion, I would hope that no one would be okay with it, simply because the tone is that to a traditional church hymn?
It is not wrong to listen to rap, if you are speaking of the genre itself (i.e. the beats, tempo, etc.). What we are believers should be concerned about are the lyrics/message of the music we listen to, regardless if its rap, rock, pop, or whatever. The Bible tells us to that ", whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirableif anything is excellent or praiseworthythink about such things." (Phil 3:8) Music is only a vehicle for the message - not the message itself.
If someone gave you a $100 bill that was dirty, beat-up, and crumbled does that mean that it is not as valuable a brand new fresh from the mint $100 bill? Oh course not!
The value hasn't changed, just the appearance.
Now apply to the discussion - the type of music can change (outward appearance), but the message does not (the value)!