Personally, I agree. But I know too many people who are willing to take the risk of Trump just to stick a finger to Clinton and DNC. I think it's foolish, but nevertheless, if there are enough of them, it may just add up.
Of course, the other side has a similar problem. Which is why I think that it's basically a contest of who can motivate more to show up to vote against the other guy. And given the potential consequences, I'd rather not take chances, even when small quantities of votes are at stake. Brexit should be a lesson to us all.