> Barbers famously talk about politics while cutting your hair. This is like a quintessential part of barber shop culture. Barbers that don't talk about partisan politics normally talk about some parapolitical thing, like cultural gripes, or sports, or other things that have a pretty similar valence.

That's not my experience at all with barbers. All they've ever talked about are topics that are considered safe for smalltalk, such as "what do you do for a living?". Of course this doesn't invalidate your experience, but I think your point about "quitessential part of the barber shop" may not be as universal as you think.