Obama's goal seems to be to appeal to a reasonable group that can talk to, rather than past, each other about abortion. If he's going to succeed, he has to confront those who perceive common ground as a threat.
The show's recent character, Dr. Benning, provides abortions later in pregnancy, like Dr. Tiller, and was shot in his church after surviving a prior shooting, like Dr. Tiller. There the similarities end.
Every woman has different life circumstances. Every pregnancy produces different challenges. Who is more able to assess the moral validity of every woman's abortion? I certainly don't think it's the Archbishop.