They're stealing ideas from comedian Tim Wilson, who wrote "First Baptist Bar & Grill".
Check out a clip of the song here:
http://www.amazon.com/exec/obidos/ASIN/B00006CTFU/qid=1088475927/sr=2-1/ref=sr_2_1/104-6574716-7416722
Pretty funny! maybe Clergy in the Bars is a Southern Tradition....