It is my oppinion that a performer should understand the music (including the historical context) he or she performs and/or the music that they are influnced by. Having said that, we are all living here and now and culture (which music is a direct reflection of) has to change over time to keep going. There is nothing wrong with a musician performing what it is they hear in a song as what they hear is theirs. I'm also a firm believer that a musician brings his/her past experiences to the stage. You really can't escape yourself onstage, so there is no point in trying to leave a personal element out of the music.