the authority to speak on racism

We've talked a lot in our class about what gives someone the authority to comment credibly on a certain racial group. There was an article in the New York times today, which is about the recent comparisons between Pope Benedict XVI and World War II Pope Pius XII. The relevant part of the article is the following quote,

"On Good Friday, the preacher of the papal household, the Rev. Raniero Cantalamessa, delivered a sermon in St. Peter’s Square, citing a letter that he said was from a Jewish friend who had compared what he called 'the violent and concentric attacks against the church' to anti-Semitism, angering both victims and Jewish groups."

My participation in this class made me notice something that I don't think I would have noticed before. In order to make this letter credible, it had to be from a Jewish friend. Not a historian, theologian, philosopher, or International Studies researcher. In my opinion, a thorough knowledge of the subject matter (history, Catholocism, etc) would make someone much more qualified to make that statement than someone who is simply, and solely identified as, a member of a specific religious group. Just an timely example of one of the recurrent themes in our class.