Is a penis a writing implement? Maybe. Certainly helps to write history with your lineage.
As for the original meaning: don't take the saying too literally. Whole families, villages and nations have been damned in the past with the stroke of a brush. It helps to have a sword by your side when you read the words "By the decree of God and so on and forth" aloud, but how many kings, emperors and popes were actually swinging it on the battle field? Not many, I presume. A few angry worded letters were sometimes enough to calm your neighbor. And how many swords can you actually order with a sword?
"By the decree of your supreme overlord, every blacksmith is now ordered to melt down 5 tons of iron in every village and forge it into anal hooks and but plugs of various sizes so our neighbor to the south will have it easier when we fuck them in the ass come this summer."