I have a brother (one of my four --- the others are not like this) who in a certain way is like Trump. He has a brain (very bright by the way) which has a defect in that it acts like a conscious force moving forward with horse blinders to all other directions, unless forced to turn directly towards them. He also has "mirrors" beside these blinders, which reflect all of reality back onto himself, as if he is the only true referent for anything. (The positive difference between my brother and Trump is that IF you can get him to redirect focus for a moment, he DOES retain some Empathy for others if they are in his focus. I do not believe that Trump has any empathy whatever.)
My experience with my brother gives me, I believe, one other "understanding" about Trump. My brother's blinders and mirrors cause him to blunder forward in his life creating all manner of "rubble" as he does so. His lack of wider perspective has him missing the rubble trail he leaves, unless someone shakes him and points it out. Trump never has anyone doing this, and has adopted the "if you disagree with me, I'll kill you" way of dealing with rubble-making. Having no empathy, Trump wouldn't care anyway.
My brother has managed a decently successful life by ignorance of half his negatives, plus overpowering the other half by talent, will power, and denial. Trump does this, or attempts to, in 100% of his rubble-making. My brother doesn't have unchecked power, plus he had a decent upbringing and family which still matters some to him. Nothing matters to Trump except himself (having no describable "policies" of any depth or long term nature should have given that away long ago. He is not a "Republican" nor anything except an ego unto himself --- Republicans should recognize this and get about restoring Republicanism; at least then we'd have a chance to proceed civilly), and he is systematically destroying any checks to his exercise of greater self-focussed power gratification.
I cannot see why ANYONE cannot be utterly upset with the direction of this. Everyone should want to put a stop to this self-centered madman.