Rick Wilson, a Republican, has a terrific essay in The Daily Beast that explains why Trump is so appealing to some people (Wilson calls them the Troll Party), and how these trolls are leading a "witch hunt for apostates" within the Republican party.
So who comprises the Troll Party? Some of them are a distaff faction of the Tea Party, angry that the leadership in Washington doesn't pursue their agenda with the bloody-mindedness and tempo they demand. Many are angry that the GOP lost to Barack Obama twice and, in their minds, allowed through action or inaction a set of economic, social, and cultural changes that make them feel powerless. For them, supporting Trump feels like rebellion. They crave a sense of agency in the face of a political culture in D.C. that they believe loathes and disregards them.
Others are reality television viewers who don't get the artifice and irony, even after almost two decades of the form. Some are walking, talking comments sections of the fever swamp sites. Some are your aunt or mom, sending the long, rambling chain emails about Obama's birth certificate with multiple forwards, fonts, colors, and glittery eagle gifs. Some pose as strict Constitutionalists, loyal unto death to the founders, except when Trump is talking.
Some of the dregs of the creepier neighborhoods of Reddit, Voat, and 4chan have joined for the lulz. The Troll Party looks at the kooks, the overt white supremacists (oh, pardon me, "race realists"), neo-Nazis, flaming anti-Semites, birthers, truthers, Jade Helmers, chemtrailers, and assorted other conspiracy whackjobs in their midst and shrugs it off with a grin.