单项选择题

Last week, the U. S. Democratic Party presidential nominee Barack Obama gave a speech in Philadelphia on race and religion. He has faced criticism because comments made by his mentor and former pastor, Reverend Jeremiah Wright were perceived to be anti-American and racially offensive. Many have called on Obama to speak out against Wright’s comments, and to turn his back on him. In the following selection, Obama explains why, although he disagrees with the man, he cannot disown him.
The man [Wright] I met more than 20 years ago is a man who helped introduce me to my Christian faith, a man who spoke to me about our obligations to love one another, to care for the sick and lift up the poor. He is a man who served his country as a U. S. Marine, who has studied and lectured at some of the finest universities and seminaries in the country, and who for over 30 years led a church that serves the community by doing God’s work here on Earth--by housing the homeless, ministering to the needy, providing day care services and scholarships and prison ministries, and reaching out to those suffering from HIV/AIDS.
In my first book, Dreams from My Father, I described the experience of my first service at Trinity [United Church of Christ].
"People began to shout, to rise from their seats and clap and cry out, a forceful wind carrying the reverend’s voice up into the rafters .... And in that single note--hope! --I heard something else; at the foot of that cross, inside the thousands of churches across the city, I imagined the stories of ordinary black people merging with the stories of David and Goliath, Moses and Pharaoh, the Christians in the lion’s den, Ezekiel’s field of dry bones. Those stories--of survival, and freedom, and hope--became our story, my story..."
That has been my experience at Trinity. Like other predominantly black churches across the country, Trinity embodies the black community in its entirety--the doctor and the welfare morn, the model student and the former gang-banger. Like other black churches, Trinity’s services are full of raucous (吵闹的；喧哗的) laughter and sometimes bawdy (色情的) humor. They are full of dancing, clapping, screaming and shouting that may seem jarring to the untrained ear. The church contains in full the kindness and cruelty, the fierce intelligence and the shocking ignorance, the struggles and successes, the love and yes, the bitterness and bias that make up the black experience in America. And this helps explain, perhaps, my relationship with Reverend Wright. As imperfect as he may be, he has been like family to me. He strengthened my faith, officiated my wedding, and baptized my children. Not once in my conversations with him have I heard him talk about any ethnic group in derogatory terms, or treat whites with whom he interacted with anything but courtesy and respect. He contains within him the contradictions--the good and the bad--of the community that he has served diligently for so many years.
I can no more disown him than I can disown the black community. I can no more disown him than I can disown my white grandmother--a woman who helped raise me, a woman who sacrificed again and again for me, a woman who loves me as much as she loves anything in this world, but a woman who once confessed her fear of black men who passed by her on the street, and who on more than one occasion has uttered racial or ethnic stereotypes that made me cringe (畏缩，恐惧).
These people are a part of me. And they are a part of America, this country that I love.
The main purpose of this paragraph is to ______.