Viet Nam was a country where America was trying to make people stop being communists by dropping things on them from airplanes.
Why were so many Americans treated by their government as though their lives were as disposable as paper facial tissues? Because that was the way authors customarily treated bit-part players in their made-up tales.
So, in the interests of survival, they trained themselves to be agreeing machines instead of thinking machines. All their minds had to do was to discover what other people were thinking, and then they thought that, too.
Ideas on Earth were badges of friendship or enmity. Their content did not matter. Friends agreed with friends, in order to express friendliness. Enemies disagreed with enemies, in order to express enmity.
Charm was a scheme for making strangers like and trust a person immediately, no matter what the charmer had in mind.