I really wouldn't say it's restricted to STW. There really does seem to be a LOT of men of a certain age who come up with false notions, impart their notions on others aggressively, then fail to accept that they maybe wrong. These notions then get passed around somehow without question.
I work in a shop, it happens quite often, a customer asks about a product or how something works, or what something does, you begin explaining to customer, then "know it all" chimes in with really bad advice, there's no stopping them once they've started. You wait for them to finish, then you've got to find a polite way to explain that "know it all" is chatting shite without causing an awkward situation so that the customer gets good info.
Serving these "know it alls" is a joke too, they ask for advice, then proceed to talk over you for half an hour with no intention of listening to a word you have to say.
Out on group rides too, the amount of wives tales you hear is nuts.
I am gob-smacked all too often by the notions based on nonsense parties favour and impart o so passionately.