I'm thinking of two old sayings:

"Never argue with an idiot. They'll drag you down to their level, and beat you with experience".

"Some minds are like cement. All mixed up and permanently set".

Social Cow, it's likely that your 16 year old was taught to do this by well-meaning, but very mis-informed parents, or some other authority figure. Scout leader, etc. Why some people insist on doing this remains a mystery, and probably always will be. They adamantly insist they are safer, even though cycling advocacy organizations, including the MA bicycle coalition, try to tell them that this is simply not the case. Explained on their website.

It's probably best to simply not say anything. Just do what you can to avoid such people.

The idiot Tri-Fecta: Riding against traffic, at night with no lights, and either no helmet, or helmet dangling from handlebars. Had anyone figured this out?