If ever I utter an oath again may my soul be blasted to eternal damnation
In our culture, the strongest swearwords are those with a sexual reference; but words which refer to God and the Devil remain mildly taboo. At any rate, we retain a folk memory of the time when they were taboo.
Superstitious people feel that it is bad luck to use the names of God and Satan frivolously; and nice people think that it's bad manners to do so. So people swear using euphemisms. May God Strike Me Blind is clearly a very offensive thing to say, but Gor-Blimey! is okay; By Our Lady is disrespectful but Bloody isn't. And which of us hasn't said zounds and sblood from time to time?
Even if these examples are apocryphal, it's hard to think that expressions like jeez! jeepers! jeepers creepers! and gee whiz! (assuming anyone ever really said anything so silly) aren't euphemisms for or corruptions of Jesus! or Jesus Christ! It works with the other kind of swearword, too. Civilization would obviously collapse if anyone printed or pronounced the word shit but we are all agreed that shite is perfectly harmless.
Dealing with swearing in stories intended for children is always a bit of a problem. Characters in Grange Hill used to say flippin' heck but we all knew what they meant. J.K Rowling has people say things like Merlin's Underpants!, which corresponds to no sort of expletive that any human being has ever used. Characters in the Beano used to say Crikey! and Crumbs! both of which are presumably divine euphemisms. Great Uncle Bulgaria used to tell young wombles off for saying lummee! although he used it himself when severely provoked. It's obviously very rude indeed, because I have no idea what it means.
American comics sometimes allowed British characters to say bloody -- the Comics Code Authority being, one assumes, unaware of what a relatively rude word the English regard it as. I just came across a 1959 Superman story in which an allegedly English villain says "You haven't got the blimey point!" which is so wrong it's inspired. But native characters didn't get to say anything so filthy. Billy Batson would say Holy Moley! and Batman's special friend Robin would use expressions like Holy Mackerel! (Jimmy Olsen says Super Duper! which makes sense, since Superman is clearly his God.)
You may, if you like, argue that "moley" is a magic herb in Greek mythology, and that mackerel was the fish used by Jesus at the feeding of 5,000 (or the thing that you should eat during Lent) but one assumes that both expressions are really euphemisms for Holy Mary!
This highly stylized form of swearing was one of many aspects of the Batman comic that were affectionately lampooned in the 1966-68 TV series. Robin in particular is given the habit of creating ad hoc swearwords by attaching the word "Holy" to some innocuous noun. "We are going to have to travel to Africa, Robin!", "Holy Travel Agent Batman!"
It seemed funny at the time. Well, actually, no it didn't.
It would be interesting to know when the last time "Holy Mackerel!" was used non-ironically in a comic-book, or, indeed, anywhere else. The Comics Code is long dead and while you probably don't get that many four-letter-words in superhero comics, Frank Miller's current version of Batman swears so much that fans have taken to referring to him as "The God Damn Batman."
So, for frick's sake, guys. I realise that the arrest of an actor after a family fight is far more important than the arrest of Radovan Karadzic. But after 40 years, five movies, and a graphic novel that even the mainstream press thought was quite good, surely you don't have to introduce every freaking item about Christian bally Bale with phrases like "Holy Arrest Warrant Batman!"