I think the GP has a fair question - the stereotype of people who label themselves 'Reverend' includes a considered reluctance to use profanity. It's not saying that reverends can't do this if they're 'real', but it is far enough out of the stereotype to ask just what kind of denomination is the author a reverend for?

Whether or not it's "written" somewhere doesn't mean that there isn't a stereotype as to how 'holy' men (it's always men...) should behave. Witness the confusion when Westerners got into Indian religions in a big way, then couldn't quite square the way some gurus shagged themselves silly - 'holy' men were 'supposed' to be celibate, if not in actuality, then at least in behaviour. It isn't the done thing to have your Anglican priest bragging about his last shagging session with his wife, for example.

Or is the author using 'reverend' as a joke appellation, without seriously being one?