Why?
Two answers, both of which are equally valid:
1. For rhetorical purposes, so nobody has the excuse of saying, "Chuck was talking smack about some goodhearted clergyman, so I didn't listen to any more of his hate-speech, tra-la-la, tra-la-la, kum-bai-yah..."
2. Beats the heck out of me. I have no more respect for him than for a bank president who cooks the books, or a CEO of Ford who tries to get people to buy GM cars. People who are Christian clergy and reject the Bible and act as if other religions are equivalent to Christ's church are either fools, snake oil salesmen or both. Even the honest ones are like surgeons who don't know or care what germ theory is.