Personally, I think swearing is only a small part of what offends people. Would the Daily Mail have jumped on the back of the Mock the Week repeat in which Frankie Boyle made a quip about the Queen's pussy if he'd made a similar joke at Kerry Katona's expense?
And essentially, it should come down to whether those words are believable in the character's mouths. The brilliance of Father Ted reflects the fact that Ted still feels the impulse to curse (it humanises him and makes him endearing) but hypocritcally, will say 'feck' instead of 'f**k' out of some flimsy pretence to his office. Jack is foul-mouthed because he's foul quite frankly, but Dougal's innocence would be compromised were he to ever utter an expletive.
Check out Frank Skinner's Panorama on Monday night about swearing.