We all know it, but dang! It's hard not to react and come to one another's defense. Many manipulators like Trump know this of course. Trump plays to one audience, and one audience only - his own. They love this stuff. Republicans will use it for cover. His true supporters will have more validation that their skewed, mean worldview is the "true" one. But, in the end, Trump's biggest reason for publicly denigrating others is to better sneak a totally unrelated deal through somewhere unnoticed, like violating the recent SCOTUS ruling on his Muslim travel ban. He's the Fagan of pick pockets, creating a commotion so that his minions can more easily separate the drawing crowd from their money undetected.