On a certain level, I completely understand why Donald Trump behaves the way he does. At times, I even like it. I especially love the way he gives the media no respect and no quarter for their dishonest and absurd behavior. I would like to see more Republicans do that. In fact, I'd like to see everyone do that, no matter who they are.
I like the fact that Trump does not concern himself with the established norms of how proper and appropriate people are supposed to behave in the political world. I don't think he's the slightest bit unaware of these norms. I think he knows very well what they are and considers them ridiculous. I think he made a calculated bet that by flouting them instead of following them, he would gain a lot more respect and support than he would lose. And I think he was right about that.
And I like the fact that Trump does not necessarily back down from fights just because the supposedly sage wisdom of seasoned old counselors would say that he should. Sometimes it makes sense to "keep the story alive" a little longer so you can set the record straight or let your attacker know that there's a price to be paid for lying about you. I don't think those sage, seasoned counselors are always right. I just think they've memorized their conventional wisdom and they think you'll consider it worth the hundreds of dollars an hour they charge you to have them spew it to you.