I am guessing, for the same reason I can have a picknick in the local park with a few friends and discuss intimate matters. This takes place in public because that is convenient, but I still don't appreciate random passers-by interjecting their opinion. It's fine to listen in though, if you're sitting close by. Most people intuitively understand this.
Online, this intuition sometimes disappears, and people feel that the fact that something is readable to them, implies it is meant for them to interact with.
It wasn't like that when I visited a few years ago. We just booked a hotel, got on a plane and went there. I can't find this requirement on their COVID page either. Do you have a link?
Online, this intuition sometimes disappears, and people feel that the fact that something is readable to them, implies it is meant for them to interact with.