I have come by claims of similar behaviour applied to all eras of missile and gunpowder warfare put forward by Grossman in 'On Killing'. Grossman's claims are quite contrived, and I'm happy to go into to detail on that if that's where you've gotten this from. Could I ask if that's one of your sources for this claim?

War time has always been a crucible for weapons and armor development. Soldiers in formation at the time would be equipped with a muzzle-loading musket that could not reliably hit a man-sized target at combat range. Long rifles were used by American sharpshooters to largely target officers in the Revolutionary War, which was considered ungentlemanly at best due to medieval traditions. The advancements in firearm technology melted away such sensibilities to the point where soldiers were encouraged to target officers.