Religious folk are prone to these sorts of back-formations. They know it's got a meaning, but they're guessing as to what it is. What they come up with is largely a function of their background. Iesus Hominum Salvator seems right to people who think Latin confers a spiritual cachet, so the embroidery on the paraments is probably Latin. Apparently, some folks think IHS stands for "In His Service." My guess is, those folks are English-speaking Protestants.
But what it also shows is that even smart people -- even smart, religious people -- are sometimes less well-informed than they think. Which is no big deal if you're the manager of the local feed store; but if you're a hot-shot opinion writer prominently featured in a national opinion magazine, you'd think you'd be a little more careful. After all, if you want people to buy your main premise, it doesn't help if you look like you don't know what you're talking about on the minor allusions you sprinkle throughout your prose.
