Donald Trump is easy to understand if you consider him to be a person with a noteworthy lack of empathy. As a man who cannot figuratively put himself in someone else's shoes, everything that thwarts his will is malice or incompetence. He lashes out because he has done everything right, but everyone around him constantly screws up (deliberately or accidentally) to cause an outcome other than the one he desires. And if the outcome he desires changes over time, then those he entrusts to carry out his wishes are deficient if they do not anticipate his vision.
(clearly, it takes an exercise of empathy to appreciate someone who lacks it)