I think @stanleybmanly and @Darth_Algar may have the right of it. At least, it makes sense that Trump is actually demonstrating how stupid so many people are, that he is getting away with this joke of a campaign. It seems far more relevant that what he’s said has been allowed to be taken seriously at all, than that he said what he said. How his actual thinking relates to his act, I don’t know. Nor do I know what the other revolting agencies (“news” media, “Republican” party, etc) responsible for their parts in the farce are actually thinking. I sort of suspect that he may bail out and be replaced by another “Republican” candidate. It’s all such nonsense, though.
Here’s an interesting article about him: http://whatever.scalzi.com/2015/12/08/eight-things-about-donald-trump/