Unspoken? I agree. I’ve never heard that rule before. That sounds like something Phil Helmuth would say in the middle of a steaming rage. “Hey Honey…, this IDIOT just raised my all-in bluff with a pair of pocket Aces, PREFLOP no less!”
The only reason I tolerate rude players is because I usually take their money, eventually. There is no money here, and therefore no reason to consider having to tolerate rude play. If a player finds another player so incredibly objectionable they feel it appropriate to belittle, degrade and insult said player, perhaps another leisure activity is in order for the intemperate player.