I think he wears them because he sometimes rides a sketchy train line late at night and he wants to be able to record if something goes down. He has normal, vision correcting lenses in them so I can’t just ask him to take them off. The best path forward to respect my friend while respecting my own privacy is to try to bring up the privacy concerns of those glasses and hope he gets the hint.

My main point is when people say things online like “if I see somebody with those I’d slap them off”. No you wouldn’t. You wouldn’t do or say anything. The person who says that online is a keyboard warrior that’s unfamiliar with real life confrontation. Your privacy is not being respected by getting into a fistfight, drawing the attention of everyone including the police. That’s not how you would solve this conflict. That’s how you become an asshole with a mugshot.