>> “No one talks on the bus. No one greets the barista ...

> Why? Bother them for no good reason?

Those 2 examples for the article are not the same situation at all... in many cultures:

"No one talks on the bus" --> very good, people are here to commute and want quiet.

"No one greets the barista" --> Wow, you're a POS human being. It's basic human dignity to greet the people you interact with.

Try the latter in a country like France for instance, skipping the "Bonjour", which is the expected cultural greeting (You're not expected to do small talk, just "Bonjour"), keep your airpods on and just place your order ... and see how the person on the other side reacts :)