[int_19h]

Conversely, that the mechanism is so old indicates that it evolved to work in groups of the size humans (or their ape ancestors even) formed back when it first appeared - i.e. dozens, not millions. It's not a given that the way we scale it is optimal, or even good.

[api]

That's sort of what bothers me. This stuff evolved to work in small tribes, not global societies. When you don't actually know the person the behavior is very different.