I'm not sure that rex doesn't. But you have a point. It is difficult to equate "dignity" with someone who hangs faked TIME covers with his face photoshopped onto it, on the walls of his clubs.
I can't give him what he denies himself. Perhaps counter-intuitively, Trumps hungry, chasmic ego destroys his dignity.
That said, there's a difference between personal dignity and human dignity.
He nevertheless deserves to be treated as any other human being. If he's not respected, he has the open microphone to blame, among many other things.
Trump's an extreme case, though. A lot of decent people voted for him. I always thought that Clinton exaggerated the number of truly despicable people who supported him.
I think a lot of people have been duped by the neo-Nazi's rebranding as "alt-right", and they've also been duped by the bifurcation of sources of journalism and information, which has been a three decade project of the right. But I don't think that's really here nor there.
I would add that while you don't earn it in the first place, human dignity is something that you can lose or diminish. Note: I'm not saying that applies to Trump supporters in general, or even to Trump himself.
Vladamir Putin is a man who bombed apartment buildings to gain power, and who murders people for business and to protect his rule. The Russian government is now run by a crime syndicate, and Trump both strongly resembles that model, and admires its architect. Am I bitter that so many of my countrymen, including many who know better, seem willing to enthusiastically usher that model in at home? Yes. Does that remove the humanity of my countrymen? No, but some of the ugliest behavior does that to them.