I think primarily it is people who still are locked into the two party shell game and think electing one of the people media force feeds them makes a difference.
The same fear that is benefiting Hillary is also benefiting Trump. Anyone that knows Hillary and the things she has done in the last 3 or 4 decades is likely truly terrified of her being president. Not for the things she says, but simply because they know the things she has already done when she had power.
So they latch onto Trump like he is the answer. Yet Trump says such outlandish things at times it has often left me wondering if the sole reason he is here is to scare people into voting for Hillary. Because, he is also proof that people are generally in politics more frightened of WORDS coming out of someones mouth than they are things the person has actually DONE.
Simplified: More afraid of a person who says they are going to kill someone, than they are of the person who has actually killed someone.
Couple that with extremely short term memories. (Lazy?) The politician's latest speech is generally the only one they remember, so they totally miss how they are so often 180 degrees from what they said in just the speech before.
Yet largely the Ron Paul people supporting Trump seem to think Trump is anti-establishment and that they are picking the Lesser of Two evils.
This is my opinion. (EDIT: I realize it seems like I agree with them... I was indicating the next part is my opinion)
As an Anarchist I do not believe we should be voting, yet I also still wrestle with this because we do not live in an Anarchistic society YET, far from it. So if I vote it is for people I see as potentially moving us closer to that. For me that'll generally be a Libertarian candidate. I do not think my vote ultimately means anything, so for me it is still me wrestling with my own conscious and not quite eschewing the system as much as I'd like to.
I haven't convinced myself doing nothing will bring us closer to where I want to be, yet I know voting is also an endorsement of system, and an authority over me they should not have.