Sadly, it’s not just bar room players. I see a majority of the recreational players of all ages (many that have likely never played a game of pool in a bar) that play in our family oriented, non-alcoholic pool room play by the same ancient rules. I guess they have been passed down to them from their parents, grandparents or others.
I stay completely out of it, unless one of them invariably asks me for a rules clarification, and I will tell them the tournament rules we play by here in all our tournaments, which are considered as our house rules, although they can play by whatever rules they choose when playing themselves.