Something I've wondered is if people who become managers are just generally more likely to be low in empathy.
The few good managers I've had in my life have generally been more of the “working class” sort who have somehow become managers but still have that experience of being one of the “little guys”. IE: they are humble.
The bad managers seem to be the ones who rise up the ranks and have little remorse, constantly make rude/belittling comments, and seem to be naturally suited to strict uncaring rule.