I wish no one would doubt children intuition about people and environment they are in ever again.

Naming the 'why' behind the emotions is a job for 12+ year old, not for the kindergartener.

The developing brain of a child may be experiencing the emotions associated with having a negative intuition, without having any of the negative stimulus that normally causes negative intuition about something.

An important part of the human developmental process is learning to calibrate these sorts of things, and one way to calibrate one's reactions is to have adults check whether the child's intuition about something was correct or not.

There can be some cases e.g. hidden abuse where the adult thinks the child may be being unreasonable where they are not, but in situations where the child and adult have equal information it's a valuable learning tool.

Most adults can't even do it reliably. The things we expect from kids that we don't even ask of ourselves....

Right, it might not even be the switch. My daughter used to scream her head off when being left in childcare. After 3 months she learned it was actually fun and looked forward to it.