A key trait of pathological narcissists is a lack of empathy. Scientists used MRIs to show narcissists have less grey matter in the area of the cerebral cortex responsible for empathy. That lack of grey matter was also found to impair memory, attention, perceptual awareness, thought, language and consciousness. 

That's the science behind Trump's inability to commiserate with others. It explains his bizarre behaviour toward war widows (along with the people of Puerto Rico and numerous other groups). 

What's more difficult to explain however is the extent to which the military, which has traditionally prized character above all else, would have voted so overwhelmingly (67%) for a man who demonstrates none - a man who avoided military service himself but who nevertheless saw fit to question the bravery of soldiers who allowed themselves to be taken alive. 

Is it that they liked what they saw in Trump or simply their discomfort with the idea of a commander-in-chief who wears lipstick?