A thought that recently came to mind about this was an article about a local homeless camp that was literally trashing the area in which it was set up. Those people have effectively been discarded by society -- so why should they care about the mess they make, after all, nobody cares about them?
So for the average voter who feels disenfranchised and abandoned by society, why should they care about what Trump says when he's famous, rich, and entertaining to watch?
That's the only way I can make any sense of the matter -- it still messes with my head.