I think that some of it is that most people don't really carefully analyze the sum total what a politician has said or is saying and all the other related material. Which is reasonable -- I mean, I know that this is a politics forum, but for most people, following politics is not a huge part of what they do. It'd be really inefficient, in fact, if they did.
I think that a lot of support for politicians has more to do whether they've made statements that a potential voter agrees with in the very limited material about them that that voter sees. Not just for Trump, but for any politician.
So if you're asking someone about Trump, they're making something of a gut call based on the limited material they see of him.
Honestly, I think that the more-interesting issue here isn't really Trump, but the fact that Trump's tactics have worked fairly well. The problem here isn't really Trump. He's just a symptom of having a political decision process that can be gamed the way he's gamed it. We do not want to encourage politicians who lose an election to have an incentive to make bogus claims that the election was rigged, because part of what we want the political system to do is to permit coming to a consensus as to leadership. That undermines that.
But there's nothing unique about Trump that permits him to do that. If he could do it, then so could another politician. And I would imagine that sooner or later, more people probably will, if they think that it is to their advantage.
That is, I think what probably needs to be fixed is the system.