[mothered]

Exactly! They either don't care or they're just that stupid.

A combination of both, probably more so the latter, hence vulnerable to SE'ing.

If the SE Is performed late (near closing time on a Friday) whereby employees are tired from and entire week's work, generally speaking, a lot of them simply want to end the call by giving the customer what he/she wants, and head off home thereafter.
Those performing social engineering, keep this In mind.