@snood,
One theory I've heard is that everyone already knows that he's a conman (pussy-grabber, inveterate liar, race-baiter — take your pick). And if you were to accuse him of being a conman he'd turn it around and take it as a compliment. "I'm such a genius I can make money just by renting out my name!" He starts out at the bottom so there's no way to fall any lower.
Another possibility is that a major percentage of his supporters actually see him as a messianic figure, just the guy we needed right now, a guy who will ignore all the stuffy conventions of political etiquette, a guy who will cut taxes, kick out the dark-skinned freeloaders and make us rich! I think that there were a good number of Democrats who, while continuing to support Bill Clinton, felt great ambivalence about his behavior. I know I did. And I imagine there are some Republicans like that, people who block out the tweets, close their eyes to the racism, and don't mention Trump's name in polite company while they re-arrange their investment portfolios. But I think there's a big swathe of the Trumpenproletariat who are simply angry and resentful, who hate the world that has dealt them a bad hand, who have compromised political immune systems that leave them vulnerable to attacks of racism and homophobia, and who actually think that destroying all our political institutions will result in some sort of tax free paradise of unbridled consumption.