Back when breach loaded guns were a new concept and up til a few decades ago primers had salt in them. That salt would cause rust in short order if not cleaned out very soon after firing. It became common knowledge and everyone taught their children to clean after use. That was taught to generations. Modern chemistry has released us from those bounds by removing salt from the mixture. Still a good idea in humid areas because powder residue still holds moisture but it won't attract it as much as the salty version.
You can't fix stupid....however ignorance can be cured through education!