People don't like a wildcard. Trump's broken promises are a little more than slight exaggerations. At this point I have to wonder if it's possible for him to lie in a way he hasn't already which will lead his supporters to recognize it as more than hyperbole. My guess is that it's not about what he says, but whether they feel he is acting in favor of their interests or not - which is really a totally different matter.
He just stood up in front of the CIA and claimed that he had more people than any Inauguration. In reality, he had less than half. The man has 0 integrity. It's not just one thing, it's everything he says. Hillary had a public and a private position - he's got so many positions his words mean nothing.
Yes, he really does seem to be behind reducing immigration. Yes, I can guess that when he stood up and told Silicon Valley's CEOs he was going to remove the borders and trade restrictions, he was probably lying. But in the end, the details are what matter, and for him to violate every single thing he says in favor of vague wishy-washy nonsense is not someone I can trust as President.